The presence of language stands as a defining human characteristic, setting us apart from other species. Even in early infancy, infants show positive responses to their exposure language's melodies and tend to withdraw from those speaking a different dialect or language (Kinzler, Shutts, DeJesus & Spelke, 2009). Across the globe, people communicate through a diverse tapestry of approximately 7,000 languages, each imposing distinct demands on its speakers (Boroditsky, 2011).

Consider this: conveying that my aunt gave five blue gloves to her friend varies dramatically across languages. In Mian, the verb choice indicates whether the event occurred recently, yesterday, or in the distant past. Indonesian verbs don't specify if the event happened or is forthcoming. Turkish verbs reveal whether I was present or heard it from someone else. Russian requires details about the shade of blue. Mandarin necessitates clarifying the aunt's relation by blood or marriage and her maternal or paternal side. In Arabic, I have to indicate the gender of her friend. In Pirahã, expressing "five" is impossible; they use words for "few" or "many" instead of exact numbers. Despite these language differences, variations in speech don't necessarily equate to different ways of thinking. How do we ascertain if speakers of Mian, Turkish, Russian, Indonesian, Mandarin, Arabic or Pirahã genuinely perceive, remember, and reason about the world differently due to their spoken languages?

The relation between language and thought

Many hold the belief that thought and language are inseparable, assuming that thinking occurs "in" language, implying that without language, thought itself ceases to exist. Helen Keller's account (1955) of recognizing the signed symbol for “water” sparking thought and emotions previously absent supports this view. Numerous intellectual figures echo similar sentiments: "The limits of my language are the limits of my world" (Wittgenstein, 1922), and "The 'real world' is largely built upon the language habits of the group" (Sapir, 1941, as cited in Whorf, 1956, p. 75). According to this perspective, without language, many thoughts may be inaccessible, and different languages might lead to different modes of thought among various human communities. But is this indeed the case?

In a practical sense, language significantly shapes thought by facilitating the transfer of ideas between minds. According to the Whorf-Sapir hypothesis, individual languages heavily influence the conceptual frameworks available to their speakers, limiting or guiding mental activities like categorization, memory, reasoning, and decision-making. This view suggests that linguistic structures act as a blueprint for an individual's mental processes. Exploring diverse linguistic systems could shed light on the varied modes of thinking cultivated or influenced by these languages. Slobin's thinking-for-speaking framework (1996, 2003) suggests that speakers tend to conceptualize events in a way that aligns with their language's structure, eventually adopting thinking patterns similar to their speech or writing habits over time.

We start with an influential example of language shaping perceptual categories: the phenomenon of categorical perception of phonemes. Initially, children can discern all acoustic-phonetic properties used by languages to convey meaning (Eimas, Siqueland, Jusczyk & Vigorito, 1971). However, around the time when language acquisition begins, infants, approximately a year old, start to lose sensitivity to phonetic differences that aren't phonemic (i.e., don't influence higher levels of linguistic structure) in the language they're exposed to (Werker & Tees, 1984).

Let's explore Pormpuraaw, where the Kuuk Thaayorre language takes a unique approach to spatial directions. Unlike English, which uses terms like left and right, Kuuk Thaayorre relies on absolute cardinal directions (north, south, east, west, etc.). While English uses cardinal directions mostly for larger scales, Kuuk Thaayorre incorporates them at every level. This means phrases like "the cup is southeast of the plate" or "the boy south of Mary is my brother" are common. In Pormpuraaw, constant orientation is necessary for proper communication.

Stephen C. Levinson's groundbreaking research over the past two decades revealed that speakers of languages reliant on absolute directions excel in spatial orientation, even in unfamiliar environments. They surpass individuals in similar settings who don't speak these languages, surpassing what scientists thought humans could achieve. Their languages cultivate and enhance this cognitive skill. Differences in spatial perception can also extend to temporal thinking. For instance, Alice Gaby and colleagues tested Kuuk Thaayorre speakers' ability to sequence shuffled photographs depicting age progressions, growth, or consumption, observing unique approaches to arranging these images to reflect correct temporal order. They conducted two tests, with each person positioned in a different cardinal direction. In this task, English speakers typically arrange the cards from left to right, reflecting the progression of time. Hebrew speakers, on the other hand, tend to organize the cards from right to left, aligning with their writing direction. However, the Kuuk Thaayorre approach time differently. They arranged the cards from east to west, adjusting their arrangement based on their seated direction—facing south, the cards progressed left to right; facing north, it was right to left; facing east, it moved toward the body, and so forth. This unique spatial orientation was employed spontaneously without any external cues about their facing direction.

Time representations exhibit diversity globally. For instance, English speakers envision the future as "ahead" and the past as "behind." In 2010, Lynden Miles and colleagues observed that English speakers tend to lean forward unconsciously when contemplating the future and backward for the past. Conversely, in Aymara, a language spoken in the Andes, the past is referred to as "ahead" and the future as "behind." Interestingly, Aymara speakers' gestures align with their language; research by Raphael Núñez and Eve Sweetser in 2006 noted that Aymara speakers gesture in front of them while discussing the past and behind them when discussing the future.

In certain languages, the organization of color categories and terms differs significantly from English. For instance, in Berinmo (spoken in Papua-New Guinea) and Himba (spoken in Namibia), there aren't distinct terms for green and blue; instead, a single word is used to encompass both colors. Research by Roberson et al. (2000, 2005) explored the phenomenon of categorical perception (CP) of color among speakers of English, Berinmo, and Himba. CP refers to the enhanced discriminability of colors that cross a category boundary compared to those within a color category. During the study, participants were shown a colored target and had to identify which of two stimuli presented five seconds later matched the target. Across each language group, performance improved when the target and distractor stimuli had different color names (e.g., in English, a blue target with a purple distractor) compared to when they shared the same name (e.g., two different shades of blue in English). Results indicated CP among all three participant groups, but specifically at color boundaries explicitly marked in their respective languages. Critically, there was no CP effect at the proposed universal boundary between green and blue for speakers of Himba and Berinmo, whose languages do not distinguish between these colors.

Languages differ in how they categorize substances, like distinguishing between mass nouns and count nouns. In many languages, including English, count nouns are commonly used for countable items and appear in both singular and plural forms, allowing enumeration. On the other hand, mass nouns (e.g., sand and dirt) cannot be counted in the same manner and don't have singular or plural contexts (*some sands and *two dirts). However, in languages like Yucatec Mayan, nouns lack the specification for individuation. Instead of indicating a unit, they refer simply to the substance or material of an object. For instance, rather than saying two candles, they might express "two units of long thin wax." Lucy (1993) conducted a study with Yucatec Mayan and English-speaking participants. They were shown an object and asked to determine which of two options were most similar, one resembling the original in shape and the other in substance. The study revealed that while English speakers favored the choice that matched in shape, Yucatec Mayans divided their preferences between the two alternatives.

In a study by Boroditsky and colleagues (2003), German and Spanish speakers were asked to describe objects with gender assignments in their respective languages. The descriptions given aligned with the predicted grammatical gender. For instance, when prompted to describe a "key"—a masculine word in German and feminine in Spanish—German speakers tended to use words like "hard," "heavy," "jagged," "metal," "serrated," and "useful," whereas Spanish speakers leaned towards "golden," "intricate," "little," "lovely," "shiny," and "tiny." Conversely, for a "bridge," feminine in German and masculine in Spanish, German speakers used descriptors like "beautiful," "elegant," "fragile," "peaceful," "pretty," and "slender," while Spanish speakers used "big," "dangerous," "long," "strong," "sturdy," and "towering." Remarkably, these differences persisted despite all testing being conducted in English, a language without grammatical gender.

Evidentiality, a linguistic feature, discloses the source of information regarding past events—whether it's from direct sensory experience, hearsay, or inference. In languages like Turkish, evidentiality is grammatically embedded, requiring speakers to specify their information source. However, in languages like English, this is more flexible and optional, expressed through vocabulary rather than grammar. In a study by Tosun, Vaid, and Geraci (2013), Turkish speakers were proficient in recognizing firsthand information, similar to English speakers. But when it came to second-hand information, Turkish speakers lagged behind English speakers. Bilingual Turkish-English individuals performed like Turkish monolinguals in Turkish tests and akin to English monolinguals in English tests. However, late Turkish-English bilinguals continued to resemble Turkish monolinguals even in English tests, showing lower accuracy in recognizing second-hand information compared to firsthand details.

Research demonstrates that altering language impacts cognitive processes. Introducing new color terms or altering temporal expressions can shift individuals' abilities to perceive colors or conceptualize time. This aligns with the Turkish saying 'one language, one person,' suggesting that each language learned shapes a distinct cognitive perspective. Considering this, when I encounter the following verses from the Quran, I interpret the purpose behind God's creation of diversity as a means for us to understand one another better and strive towards personal growth and improvement.

And among His signs is the creation of the heavens and the earth, and the diversity of your languages and colors. Surely in this are signs indeed for people who have knowledge (of the facts in creation and who are free of prejudices). (30:22)

O humankind! Surely We have created you from a single (pair of) male and female, and made you into tribes and families so that you may know one another (and so build mutuality and co-operative relationships, not so that you may take pride in your differences of race or social rank, and breed enmities). Surely the noblest, most honorable of you in God’s sight is the one best in piety, righteousness, and reverence for God. Surely God is All-Knowing, All-Aware. (49:13)

References

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