In Chinese, foreign words are called wailai ci or wailai yu, referring to words adopted from another language, ones that come from abroad. Foreign words play an important role in enriching the language and culture of a society. Influenced by political, social, and cultural factors, heretofore unknown ideas or items are introduced into that society and since no language is entirely self-sufficient, when those things need to be described or named, words from the originating language become a source of inspiration.

Throughout history, every significant cultural influx into China arrived with a large number of foreign words which were incorporated in one fashion or another into the Chinese language. When Buddhism, which began in South Asia, began to become widely known during the Eastern Han dynasty  (25–220), many Buddhist terms, originally rendered in Sanskrit, became, in modified form, a part of everyday Chinese speech. Similarly today, the development of information technology, which mainly occurred in the Euro-American world, has brought to China new phrases and words, a technical vocabulary of cyberspeak of primarily English origin.

During the Han dynasty (206 BCE–220 CE), China’s relations with non-Chinese peoples and states greatly expanded. Especially important was the relationship between China and the Xiongnu (a confederation of nomadic peoples who inhabited the eastern Asian Steppe from the third century BCE to the late first century CE). In pre-Han times they seem to have been included in a general grouping of non-Chinese called hu. Some scholars assert that the Xiongnu people called themselves “Hu,” a word meaning both human and god. In any case, from the Han dynasty onward the term “Hu” became widely used in Chinese, sometimes specifically connected to Xiongnu, sometimes more generally connected to non-Chinese primarily from the north and west of China. New words like huqin (the Hu fiddle ), erhu (the two-stringed fiddle or spike fiddle), both musical instruments played with bows and hujiao (Hu pepper or black pepper) emerged along with these introduced items. A now standard phrase in Chinese meaning to speak gibberish or nonsense, hushuo badao literally means “A Hu speaks of the Eight-fold Path” and seems to have been originally intended to be critically descriptive of the unintelligible manner in which a foreigner describes something, in this case the Eight-fold Path of Buddhism. 

During the reign of Emperor Wu (r. 141–87 BCE) of the Han dynasty, there was great expansion of trade between China and other parts of the world. The Chinese engaged in commerce with the various inhabitants of Xiyu, or the Western Regions (a historical name that referred to the regions west of Yumen or Jade Gate Pass located in modern Gansu province), and trade extended beyond regions directly contiguous to the Han empire. These included Central and Western Asia as well as South Asia not to mention the Arabian Peninsula and Mediterranean Europe. This international commerce brought information about things new to China, including foreign words to describe them. Among the most widely adopted were some from the Western Regions such as shizi, the word for lion adopted from Tocharian, and pipa, a plucked short lute, which seems to be of foreign origin and  whose name may also derive from a Central Asian or Western Asian language.

Buddhism, originating in South Asia was introduced to China through the Western Regions and with came a number of new words. In its early history in China, Sanskrit words such as Buddha, meaning “Enlightened One” and Arhat meaning “Worthy One” were transliterated into Futu and Aluohan respectively. This imitation in Chinese of sound rather than meaning evolved into Fo for Buddha and Luohan for Arhat.

In the post-Han era, from the Wei (265–420) and Jin (265–420) dynasties through the Sui (581–618) and Tang (618–907) dynasties, many Buddhist words entered Chinese. Some of them derive from Sanskrit  originals, sometimes in a mixture of transliteration and paraphrase of meaning or one or the other. These include puti (enlightenment), from bodhi; chan (meditation) from dhyāna; qielan (monastery, temple, etc.) from saṃgha-ārāma; yujia (union), from yoga; chana (instant, which is about 0.08 second) from ksana and jiasha (robes of Buddhist monks) from kāṣāya. The word heshang (monk) is also from the Western Regions, most likely from the Sanskrit, upādhāya, indicating a religious instructor or “preceptor,” and refers to senior Buddhist priests. From this time on commercial activity and foreign trade expanded, and there was both continual introduction of new things and words from abroad. Many of these foreign products and words are still in common use today. Among these are the words pingguo (apple); bocai (originally bolengcai, spinach) and doukou (cardamom or Elettaria cardomomum) derived from South Asian languages. The word falang for enamel is another example, believed to taken from the Persian farang.

Some foreign words have been simply transliterated or transcribed into Chinese, such as caomei (strawberry, literally ‘grass berry’) and kafei (coffee) but some are paraphrased as to meaning for example, jiguang (laser, literally “ray of stimulation”). Some translations are combinations of transliteration and paraphrase. For example, the English word Utopia, itself a coinage from Greek meaning “no place” but one that is ideal or nearly perfect is translated in Chinese as Wutuobang, which echoes the original’s sound but meaning, too, as it can be interpreted as “no place except out of the imagination.” Some foreign words in Chinese borrow both the pronunciation and written form from the source language; many words of this category are from English or Japanese. These include MTV (Music Television) taken directly from English and julebu (club) from the Chinese pronunciation of the characters (kanji) used in Japanese to transliterate the English word club in Japanese, kurabu. Some words are half paraphrase and half transliteration; for example, New Zealand is Xinxilan in Chinese. “Xin” is the Chinese word for the meaning “new” but “Xilan” is the transliteration of “Zealand.” Many Japanese words entered Chinese by directly transcribing Japanese kanji into Chinese characters, such as jingji (economy) and wenming (civilization), in Japanese these words having the same meaning, but with different pronunciation, e.g., keizai (economy) and bunmei (civilization).