Each sign language has its own distinctive vocabulary: ideographic sign signs that identify individual words, sometimes short sentences. Their number in different languages varies from 5,000 to 15,000 characters. They are the basis of linguistic communication. The ideographic signs are complemented by typing signs, which consist of the alphabet of the fingers, that is, a set of characters that denote individual letters of the alphabet (also some digraphs, such as sz, cz, rz), signs of cardinal and ordinal numbers, regular and decimal fractions, etc.
Finger alphabets are now an integral part of sign languages and are related to conceptual signs, although they are much closer to sound languages, and in particular to their written varieties. They correspond to letters in which each word of a phonic language can be segmented, but there is no such possibility to segment an ideographic sign into letters.
For this reason, in classical sign language there are no inflectional endings, but the influence of the alphabet of the fingers on the formation of new signs in sign languages is evident, which often use the arrangement of the fingers characteristic of the alphabetic characters of the fingers, corresponding to the letters starting a given word there are ideographic signs corresponding to the concepts of who, who, who, what, us, you, volume, important, or certain days of the week, etc. (Lane H 1996).
Sign language has its own specific positional grammar, where word order determines the meaning of a sentence. The emergence of such grammar is due to the fact that ideographic signs have a fixed form – they do not have variations for cases and people, so the grammatical structures must be obtained differently.
This type of grammar, however, means that from Polish to sign language (and vice versa) it is not possible to translate word by word, but to construct the translated sentences in the form of exhaustive structures, according to the grammar rules of the language in which you are currently translating. .
The same phenomenon also occurs in translations from one audio language into another audio language: when translating, for example, from Polish to English, the translated sentences must also be constructed according to the grammar rules of a foreign language. A specific feature of sign languages is also the spatial organization of expressions, which allows a precise description of reality using a much smaller number of sign signs than words in audio languages.