Lexical gap

A lexical gap or lacuna is an absence of a word in a particular language. Several types of lexical gaps are possible, such as untranslatability, missing inflections, or nonsense words.

Translatability
Often a concept lexicalized in one language does not have a corresponding lexical unit in another language and thus presents a translation difficulty. Circumlocution, a descriptive phrase, must be used instead, or possibly even multiple phrases used in varying situations. For example, Romanian lacks the word "shallow". Therefore, "shallow waters" is mainly translated as "ape puţin adânci" ("not so deep waters") or "apă mică" ("small water") in TV subtitles.

In most languages, if the missing concept is important or must be cited often, borrowing from one language and adding to another may occur.

This case should not be confused with translation into a different type of lexical unit. For example, a simple word may be translated as a compound or a collocation, as in the cases of the Russian word "bosoy", which is translated as the compound "barefoot" in English, and the English word "private" (in the sense of a military rank), which is "soldato semplice" in Italian.

An abundant source of lexical gaps used to be a contact of primitive cultures with more advanced civilizations. For example, the Russian ethnographer Miklukho-Maklai, famous for his study of the aborigines of New Guinea, recorded that Papuans, who have never seen an ox, gave the animal a name back-translated as "a huge pig with teeth on the forehead".

Missing inflection
Sometimes a certain inflection of a word produces a word phonetically forbidden or awkward in a given language. For example the Russian word 'dno' in the meaning of bottom (of a barrel or a river) does not have a plural form.

Nonsense words
Due to phonotactics, a language may have restrictions on what kind of sounds can come in certain positions of a word. There exist nonsense words that obey all the phonotactics of a language, but yet have no meaning. A word such as "bluck" obeys the phonological and phonotactic rules of English, yet a meaning does not exist for it, so it is a lexical gap in English.