On the interplay of external and internal factors in the development of language

This article deals with the relationship between the internal and external factors that affect the development of language. Vachek is primarily interested in the levels of phonology and grammar, providing ample examples from English, a language that has been affected by numerous external factors in its development. He considers how external factors affect the phonic level, but notes that the operation of the external factors is possible only as far as the internal factors actually allow the former to be asserted. More specifically, he discusses the difference between negation in Czech and English, noting the change from multiple sentence negation in Old English to single sentence negation in Modern English. On the level of phonology, he also notes how the historical fate of certain phonemes (their gradual disappearance, preservation, phonologization, etc.) depends on the internal arrangement of the system and its changing balance, which is sometimes upset by external factors, e.g. the need of the language to incorporate foreign elements coming into the system.