consequences on grammar:
During language loss—sometimes referred to as obsolescence in the linguistic literature—the language that is being lost generally undergoes changes as speakers make their language more similar to the language that they are shifting to. This process of change has been described by Appel (1983) in two categories, though they are not mutually exclusive. Often speakers replace elements of their own language with something from the language they are shifting toward. Also, if their heritage language has an element that the new language does not, speakers may drop it.
- overgeneralization;
- undergeneralization;
- loss of phonological contrasts;
- variability;
- changes in word order;
- morphological loss, such as was seen in Scottish Gaelic in East Sutherland, Scotland (Dorian: 1978) as fluent speakers still used the correct plural formation, whereas semi-speakers used simple suffixation or did not include any plural formation at all;
- synthetic morphosyntax may become increasingly analytic;
- syntactic loss (i.e. lexical categories, complex constructions);
- relexification;
- loss of word-formation productivity;
- style loss, such as the loss of ritual speech;
- morphological leveling;
- analogical leveling.