Interlanguage speakers typically prioritize meaning and will communicate first and foremost with whatever lexical resources they can mobilize. This may mean using approximate terms, L1 terms or terms from another known language, or paraphrasing.

Interlanguage speakers (depending on their proficiency) typically need to simplify the grammar of the language. This means that morphological features such as tense markings, determiners and agreement marking of the target language may be missing or variable: often, one form will be overgeneralized to all contexts (eg don't speak, don't appreciate; einen Hut, einen Hund, einen Man)

Influence from the interlanguage speakers' L1 is often present in:

• lexical areas, such as 'borrowing' (eg picture, bowtie), using 'cognates' (appreciate) and the literal translation of phrases (ich weiss nicht dieses);
• reinforcing simplification of the TL grammar, eg the French learner may have missed que in Je pense ø la femme est vieux and failed to select the feminine form of the adjective because of influence from English;
• confusion over use of grammatical forms which appear similar to the L1 but which are used differently: eg the English learner's overuse of this may be due to different usage of ce (this) and le (the) in his L1 French; the Spanish learner's confusion over suya and suyo may be caused by differences in how English and Spanish possessive adjectives change according to gender (either the gender of the noun being possessed, as in Spanish, or the gender of the possessor, as in English).

We shall now investigate some of these features in more detail and attempt to explain how and why they arise.