Research on subtitle translation abroad began in the mid-20th century, and it was only after film and television works were spread to various countries that they gradually entered the academic horizon. In 1956, the International Federation of Translators published an article entitled Film and Translation in its own Babel journal, which was regarded as the earliest systematic discussion of audiovisual translation. It is generally believed in the academic community that this milestone development marks the official beginning of European audiovisual translation research and has also promoted the academic exploration of this field worldwide. [3] discussed how the translator’s qualifications, translation methods, and personal understanding will affect the quality of translation by analyzing errors in translation. [25] proposed the concept of “restricted translation” and laid the groundwork for the theoretical framework of this emerging discipline.

By the 1990s, the research perspective of subtitle translation had changed significantly, and more systematic theories emerged. Researchers began to pay attention to technical factors and the role played by the audience in subtitle translation. Some linguistic theories related to subtitle translation were put forward. For example, [7] summarized ten subtitle translation strategies. In 2004, Gottlieb defined subtitle translation as “cross-symbol translation in multi-symbol media (film, television, video and DVD), presented in the form of a line or more lines of text on the screen, and synchronized with the original dialogue” ([8]). At that time, the research was obviously more systematic and interdisciplinary.

After entering the 21st century, research in this field has ushered in a stage of rapid growth and increasingly diverse themes, and documentary subtitle translation has gradually become an important specialized direction. Scholars discuss this problem from several angles: [21] believed that the key factor of translation quality plays a great role in documentary translation, and whether the translation is good or not depends on the audience’s reaction. He also emphasized that the translator is actually at the center of the whole translation process. [4] compared documentary subtitle translation with other types of film and television translation, pointing out its uniqueness from five aspects: mode of discovery, field, translation mode, audience design, and text function.

Overall, judging from the historical context of subtitle translation research abroad, it has gradually developed into a relatively mature academic field. At first, everyone mainly focused on technical problems, and then slowly expanded to cultural adaptation, audience acceptance, and different types of subtitles. However, sub-fields such as documentary subtitle translation are still under development and are not fully mature.

Domestic research on film and television subtitle translation began in the 1990s, which is later than in the West. However, after nearly 30 years of development, there is now a clear research scope and a complete theoretical framework. According to the statistics of China National Knowledge Infrastructure (CNKI), so far, 2,888 relevant publications have been retrieved with “subtitle translation” as the keyword, indicating that this field has been attracting the attention of the academic community.

[17] put forward five principles of film and television subtitle translation: colloquialism, personalization, emotionality, oral style, and popularization. He also introduced the concept of the “dubbed film” in his article, which laid an important foundation for the study of audiovisual translation in China.

[22] made a systematic comparison of the differences between film and television subtitle language and written language, and summarized five obvious characteristics of subtitle language: audibility, immediacy, comprehensiveness, popularity, and the absence of annotations.

In the article Strategies for Translating Subtitles, [16] analyzed the text characteristics of subtitles under the limitation of time and space in depth. He advocated the “reduction” method for translation, and also proposed five ways to deal with culture-loaded terms, and emphasized that successful subtitle translation should achieve the integration of image, sound, and text under technical limitations. In addition, [1] pointed out that the study of subtitle translation is still at an early stage, and it is also relatively marginal in the field of translation. They believed that future research should focus more on the micro level, especially specific translation skills, and pay more attention to practicality and operational applicability.

All in all, domestic scholars have paid a lot of attention to the translation of film and television subtitles in recent years. However, most of the relevant research has focused on the characteristics of movie subtitles and specific translation strategies and methods, and the translation of documentary subtitles has not received enough attention ([26]).

Unlike [26], who examined the same documentary from the perspective of Skopos theory with a focus on translation purposes, this study adopts Eco-translatology to reveal the translator’s adaptive selection mechanisms across multiple ecological dimensions. By focusing on how the translator balances linguistic, cultural, and communicative needs in specific examples, this study aims to provide a more dynamic and operational account of subtitle translation within the framework of Eco-translatology.

Eco-translatology was proposed by Professor Hu Gengshen, which can be understood as a translation research method from the perspective of ecology. This theoretical approach is part of a broader functionalist tradition in translation studies, which includes scholars such as Reiss K, Reiss and Vermeer H, and Nord C, who emphasized translation as a purposeful, target-oriented activity. [24] emphasized that translation criticism should move beyond purely linguistic equivalence to include functional and pragmatic criteria, arguing that “the ideal translation would be one in which the target text is equivalent to the source text in terms of conceptual content, linguistic form, and communicative function.” Furthermore, Vermeer ([23]) formulated the Skopos rule as the overarching principle: “The prime principle determining any translation process is the purpose (Skopos) of the overall translational action.” [19] further refined functionalist approaches by proposing the principle of function plus loyalty, arguing that translators have a responsibility to mediate between the source-text author, target-text readers, and the client, balancing the intended function of the target text with loyalty to all parties involved in the translational interaction. In 2001, Hu proposed “Translation as Adaptation and Selection” at the Third Asian Translators’ Forum. This concept was later explained more systematically in the 2004 monograph; he redefined translation as a dynamic process: translators should constantly adapt to the “translation ecological environment” and make choices at the same time ([10]). The so-called translation ecological environment refers to a world composed of the source text, the source language, and the target language, which not only includes linguistic, cultural, communicative, and social dimensions of translation, but also includes the interrelated and dynamically changing relationship between the author, the client, and the reader ([11]).

Professor Fang Mengzhi believed that the translation ecological environment is actually derived from a variety of concepts and theoretical principles. It provides a very in-depth observational perspective for the development of ecological translation, which can be said to be the support of the whole discipline structure. This concept is significantly useful in understanding the basic principles, theories, and concepts of the discipline ([5]). It can be said that the eco-environment of translation is a core concept in Eco-translatology.

The theoretical foundation of Eco-translatology actually takes into account the macro and micro levels of translation. The core concept is the translational ecosystem, which means that translators should make adaptive choices between the source and target texts to play an intermediary role, and at the same time find a balance between the suitability and cultural consistency of the translation. At the macro level, there are ecological paradigms and the translator’s ethical responsibilities; at the micro level, it focuses on how to operate, such as the Three-dimensional Transformation Theory—linguistic, cultural, and communicative adaptation. Putting these dimensions together can answer several fundamental questions of translation: What is translation? (contextualized text transplantation); Who is translating? (The translator acts as a decision-maker); How to translate? (Cross-dimensional adaptation, selection, and transformation); Why translation? (Pursue better results in cross-cultural communication with a specific purpose) ([13]).

To ensure analytical consistency, three key terms are operationally defined as follows:

Multidimensional adaptation refers to the translator’s ability to simultaneously make adaptive choices across the linguistic, cultural, and communicative dimensions to fit the translational eco-environment.

Ecological balance denotes a state in which the target text achieves equilibrium among fidelity to the source text, readability for the target audience, and successful transmission of communicative intent.

Obscure information refers to expressions in the source language whose meaning is not directly accessible through literal translation due to cultural specificity, metaphor, implicit logical relations, or specialized knowledge, thereby requiring the translator to adopt explicitation, generalization, or omission strategies.

3.2.1. Adaptive Selection and Transformation at the Linguistic Dimension

The adaptive selection and transformation at the level of language refer to the translator’s ability to appropriately adjust or convert language elements in the translation process ([12]). When translating, translators should pay attention to the differences between the source language and the target language in terms of vocabulary, syntax, etc., and then make the necessary conversions in a targeted manner, so that the translation can be both accurate and smooth.

3.2.2. Adaptive Selection and Transformation at the Cultural Dimension

The cultural dimension of adaptive selection and transformation emphasizes the translator’s role in bridging and interpreting cultural connotations across source and target languages. This approach underscores the significance of recognizing distinctions in both the essence and substance of the source and target cultures, thereby preventing potential misinterpretations from the perspective of the target culture. When converting the source language into the target language, the translator also needs to take into account the larger cultural context behind the language. As [20] argued, translating culture-specific items requires a functional decision about whether to preserve the source-culture reference or adapt it to the target-culture context.

3.2.3. Adaptive Selection and Transformation at the Communicative Dimension

Adaptive selection and transformation at the communicative dimension are characterized by the translator paying attention to the adaptation of the communicative intentions of the source language into the target one ([12]). The transformation at this dimension requires going beyond the translation of linguistic and cultural aspects, which should be directed towards the successful transfer of the intended meaning from the source text into the target text.

Based on the typology of subtitles, the translation in the documentary film Seasons of China represents an example of interlingual subtitling. In this case, the Chinese (source text) narration needs to be translated to English (target text) subtitles while retaining the integrity of the source text in terms of culture, emotion, and information. Based on its stylistics, content, and format, this study identifies four main characteristics of the subtitle language, including transience, conciseness, richness of culture, and communicability.

Subtitle language is different from general text due to the simultaneous restriction of both time and space in terms of format and the necessity for audiovisual interaction in terms of content. Subtitle language is shown and hidden at exact moments based on visual elements and narration, and translated subtitles need to appear within limited periods of time. Otherwise, the readers will not have enough time to finish reading before new scenes change. Moreover, considering that there is limited screen space, the length of subtitles should be brief. Hence, there is a notable characteristic of transience and conciseness in subtitle language.

Richness of culture refers to the role of subtitle language in delivering cultural information. For example, Seasons of China includes many culture-loaded terms based on traditional Chinese philosophies, astronomy, and agricultural civilization. Accurately delivering the meaning behind such temporal concepts, folk customs, and philosophy of nature is of great importance for subtitle translation.

Moreover, from the perspective of communicability, we need to understand that not only should accurate information be delivered through subtitles, but it should also help to engage the audience in the process to facilitate understanding. The narration of Seasons of China is based on solar terms and thus delivers the wisdom of harmony between nature and mankind. Subtitle translation in Seasons of China needs to communicate facts and evoke emotions from the Chinese perspective towards nature and culture.

This paper adopts the method of text analysis, taking the documentary Seasons of China as the specific analysis object. The Chinese source dialogue and the English target subtitles were both transcribed manually by the author from the documentary. The selection of episodes (3, 4, 5, 9, 10, and 13) was based on the following rationale: Episode 3 introduces the solar term “Jingzhe” (Insects Awakening) and related folk customs; Episode 4 covers Qingming Festival and agricultural traditions; Episode 5 features Dragon Boat Festival rituals; Episode 9 contains dense agricultural sayings; Episode 10 focuses on birthday and longevity culture; and Episode 13 discusses Beginning of Autumn and harvest-related ceremonies. The selection of cases follows these principles: firstly, they should encompass the linguistic, cultural, and communicative dimensions; secondly, try to choose those expressions that are heavily culture-loaded and difficult to translate; finally, 11 representative examples are selected from the above episodes for a more detailed analysis. The analytical procedure was as follows: each candidate example was first identified as containing a translation challenge related to one or more of the three dimensions. Then, the author categorized it according to the dominant dimension exemplified (e.g., Example 1 for parataxis and hypotaxis in the linguistic dimension; Example 7 for culture-loaded festival names in the cultural dimension; Example 10 for obscure idioms in the communicative dimension). Each selected example was then analyzed by comparing the source and target texts, identifying the translation strategy used, and explaining how that strategy reflects adaptive selection within the framework of Eco-translatology. This approach aims to systematically explore the translator’s adaptation and selection strategies across different ecological dimensions.

5.1.1. Parataxis and Hypotaxis

Hypotaxis and parataxis are two different modes of organizing languages. According to [9], hypotaxis refers to the linking of clauses by means of subordination, where one clause is dependent on another, while parataxis involves the linking of clauses by coordination, where clauses are of equal status. These two modes represent fundamental grammatical choices in clause-combining strategies across languages ([9]). Hypotaxis involves the subordination of one clause to another, characterized by clear boundaries, tight structure, and explicit hierarchical relationships. In contrast, parataxis refers to the connection of words and clauses without overt logical connectors, where semantic relationships are conveyed directly. As Chinese belongs to the Sino-Tibetan language family and English to the Indo-European, the two systems display markedly different organizational principles. As [15] observed, Chinese syntax is characterized by a strong preference for parataxis, where clauses are often juxtaposed without explicit conjunctions, relying instead on semantic and pragmatic inference. In contrast, English typically requires explicit markers of logical relations ([15]). Chinese often de-emphasizes formal syntactic links between clauses, resulting in a relatively flexible sentence structure. As for English, it not only pays attention to the expression of meaning, but also to the logical coherence of the form. It usually uses various grammatical means such as conjunctions and participles to maintain the integrity of the structure. [6] similarly noted that paratactic structures are often used in narrative to create a sense of immediacy and chronological sequence, whereas hypotactic structures allow for more complex logical subordination.

Example 1:

ST: 祠堂的建立，让他们有了一个地方，可以聚集在一起祭祀祖先。

TT: Ancestral halls are built so they have a place to gather and make offerings to their ancestors. (Episode 3:14:37)

Example 2 :

ST: 现在正好是惊蛰，这些虫开始有声音了。

TT: Right now is the Insects Awakening, and the insects are beginning to get noisy. (Episode 3:07:01)

In Example 1, the two short sentences are juxtaposed. Instead of using obvious logical conjunctions, they rely on semantic flow and context to imply causality (“because ancestral halls are built, they therefore have a place to gather”). The English translation “Ancestral halls are built, so they have a place to gather” introduces a clear sign. The translator adds the conjunction “so” to clearly point out this causal connection, thus adjusting the sentence style to fit the English preference for explicit logical conjunctions. This conversion from parataxis to hypotaxis directly expresses the original implicit relationship, which is clearer for the English audience.

In Example 2, the connection between the solar term “Insects Awakening” and what happened later is more implicit at the cultural level than reflected by grammatical marks. The English translation “Right now is the Insects Awakening, and the insects are beginning to get noisy” adopts a mixed strategy: it uses the coordinating conjunction “and,” which is actually a very weak hypotactic form. This treatment largely retains the paratactic flavor of the source text, so that the cultural term “Insects Awakening” itself can explain why insects begin to make a fuss. This translation is a compromise—only adding the smallest hypotactic component, while maintaining the relative independence between small sentences, which is also closer to the feeling of semantic juxtaposition in the source text.

5.1.2. Active Voice and Passive Voice

Another obvious difference between English and Chinese is the voice of the sentences. From the perspective of systemic functional linguistics, voice is a grammatical category that reflects the speaker’s choice in representing the relationship between a process and its participants; the passive voice allows the speaker to place the affected participant in the subject position, thereby reorienting the information focus ([9]). Active voice is used more in Chinese, and the scope of application of the passive voice is relatively limited. When the subject of the sentence is not clear, passive voice is sometimes used to maintain contextual coherence. In English, passive voice is a very common structure, because it can avoid the introduction of subjective factors and make the description more objective.

Example 3:

ST: 我还没进屋，浓浓的草木香气就已扑鼻而来。

TT: I haven’t even set a foot inside, and I am already struck by the overpowering smell of these potions. (Episode 4:04:33)

Example 4:

ST: 船变成了每年清明祭祀活动的道具。

TT: So the boat is now reserved for the Qingming Festival. (Episode 5:09:17)

In Example 3, the Chinese sentence completely uses the active voice: the subject “I” has performed the action of “还没进屋”, while the “草木香气” actively “扑鼻而来”. The English translation made a strategic change in tone: the first clause retains the active structure (“I haven’t stepped”), and the second clause is changed to a passive structure (“I am already struck by”). This treatment not only retains the semantics of the narrator’s acceptance of sensory experience in the source text, but also remains unchanged. Although the grammatical voice has changed, the narrator’s subjective sense of the focus of the subject has not been lost, indicating that the translator has made a functional adaptation in this context to be close to authentic English expression.

In Example 4, Chinese sentences use active voice, and the subject “船” is the sender of the action “变成”. The English translation is deliberately changed to passive voice, so that the boat as the grammatical subject corresponds to “is reserved”. This transformation has a specific rhetorical purpose: passive voice reorganizes information and emphasizes the new state or purpose of the ship, not the process of its change. This aligns with Halliday’s observation that passive voice serves to place the “goal” of the process in thematic position, thereby altering the focus of information ([9]). In this way, the tone of the translation is more formal and objective, which is in line with the narrative style of the documentary. It also inadvertently draws attention to the specific role of the ship in the sacrificial tradition, so that the grammatical structure is consistent with the cultural customs and the focus of the theme of distribution.

Free Translation with Literal Translation

The method of combining literal and free translation aims to preserve the linguistic features of the source text while taking into account the cultural context of the target language and the comprehension of its readers. In this approach, the translator retains the original pronunciation or form of certain proper nouns or culture-loaded terms through transliteration, while also employing free translation, often with annotations or explanations, to convey their deeper meaning. The following examples illustrate the application of free translation plus literal translation to solve translation problems from the perspective of the three-dimensional transformation principle.

Example 5:

ST: 长寿面

TT: Long-life noodles (bowls of noodles for health and longevity) (Episode 10:01:43)

Example 6:

ST: 春种一粒粟，秋收万颗子。

TT: In spring, plant just one grain, and in autumn you can harvest ten thousand. (Episode 4:17:10)

Example 7:

ST: 龙抬头

TT: Dragon Heads-raising Day (Episode 3:01:47)

Example 8:

ST: 立秋

TT: Liqiu, the Beginning of Autumn. (Episode 13:01:40)

Example 9:

ST: 秋社

TT: offering sacrifices to the Earth God (Episode 13:01:40)

In Example 5, “长寿面” is translated as “Long-life noodles (bowls of noodles for health and longevity)”. Here, the core word uses an almost literal translation to directly retain the compound structure of the original word. However, this kind of literal translation may not fully convey the cultural symbolic meaning of this dish in terms of celebrating life and praying for longevity, so the translation adds a free translation in parentheses as a supplement. This combination method not only retains the image of the source target, but also clearly points out its cultural function and implicit meaning.

In Examples 7 and 8, similar combination strategies are also used for culturally specific festivals. “龙抬头” was translated as “Dragon Heads-raising Day”. The core metaphor uses literal translation to retain its vivid image. Adding the word “Day” is a free translation strategy: it classifies the term into a familiar conceptual category (a festival or anniversary) for the target audience, which not only helps with understanding, but also does not distort the core image.

Similarly, in Example 8, “立秋” is translated as “Liqiu, the Beginning of Autumn”. Here, the combination of two parts is used: the previous “Liqiu” is a literal transliteration, which retains the original pronunciation and terminology identity; the following is the free translation “the Beginning of Autumn,” which directly explains the core meaning of this solar term. This combination not only introduces the exclusive concept of this culture to the readers, but also ensures that its semantic content can be understood immediately.

In Example 6, the poem “春种一粒粟，秋收万颗子” is translated as “In spring plant just one grain and in autumn you can harvest ten thousand.” Here, free translation is mainly used to convey the proverbial meaning of sowing and harvesting, as well as the feeling of natural abundance. The translator adjusts the structure to make it closer to the natural expression of English poetry, while retaining the core digital contrast between “one grain” and “ten thousand grains.” That is to say, although the specific digital concept is from the literal transliteration, the rhythm and syntax are flexibly handled according to the target language.

“秋社” in Example 9 also can be regarded as a strategy based on free translation. It was translated as “offering sacrifices to the Earth God”. With a purely literal translation (for example, rendered as “Autumn Society”), it would be obscure and unclear what it means. The translator chooses to put aside the original form and directly convey the core of this cultural activity, that is, the ritual of sacrifice. In this way, the priority is functional equivalence and readers’ understanding, which clearly explains the purpose of this festival. Although this practice does not retain the form of the original word, it fits the overall context of the documentary.

Obscure Information

There are many obscure expressions in Chinese, and it is often not clear to explain the meaning by literal interpretation alone. Such ambiguous expressions also appear in the subtitles of Seasons of China, which brings considerable challenges to translators. Therefore, how to reconstruct the vague parts in this source language and effectively convey the content to the audience becomes a core task in the translation process. From the perspective of linguistic communication, [14] argued that the referential (or communicative) function of language is oriented toward the context, requiring the message to be clear and unambiguous. When faced with culturally opaque expressions, the translator must intervene to ensure the communicative intent is successfully transferred.

Example 10:

ST: 立秋节气的晚上，翅膀硬了的蛐蛐儿遍地蹦跳，但千军易得，一将难求。有经验的捕虫人往往通过叫声听出蛐蛐儿的优劣。

TT: In the autumn night, fully grown crickets spring about in their thousands. However, to pick out the exceptional from the ordinary is a daunting task. (Episode 13:03:56)

Example 11:

ST: 俗话说春争日，夏争时，过了芒种争回耧。

TT: As the saying goes, in spring, you can count in days, but in summer, you have to count in hours. (Episode 09:05:10)

There are two main layers of vague expressions in Example 10. The first is the metaphor of “翅膀硬了的蛐蛐儿,” which actually describes the state of maturity and readiness. If it is a literal translation, the audience will not understand it. The translator uses free translation and interpretation to translate it into “fully grown crickets,” which not only accurately conveys the core meaning (mature and combative crickets) but also abandons the unfamiliar metaphor. The second, and more difficult, part to deal with is the proverb “千军易得,一将难求.” This classic idiom has rich cultural connotations and is difficult to understand. The translator chooses a strategy of cultural substitution and generalization. It is rendered as “to pick out the exceptional from the ordinary is a daunting task.” This translation successfully extracts the core meaning of the proverb—it is tough to find a rare best among many ordinary individuals—and then re-encodes it into a clear, abstract, and fully suitable English sentence that fits the context of selecting the best cricket.

In Example 11, the first half of the sentence uses parallel structure to emphasize the increasingly urgent situation of farm work with the change of seasons. The translator handles this through semantic explicitation and rhythmic adaptation, producing “in spring, you can count in days, but in summer, you have to count in hours.” It effectively clarifies the “count” metaphor into a clear comparison of time-unit urgency, making the seasonal pressure immediately understandable. The last sentence is quite obscure. It mentions a specific farm tool (“耧”, a seed drill) and its use after the “Grain in Ear” solar term. This is relatively deep cultural knowledge related to specific operations. Confronted with this challenge, the translator adopts strategic omission, leaving the clause untranslated.