This limitation is especially acute in second language learners. This fact is further supported by research in computational analysis of language. Lexical phrases are a way of overcoming such constraints because they are stored as wholes and are therefore readily accessible. This means that learners do not need to pay attention to grammar if they use these phrases. By shifting their attention from grammar to features such as relevance, coherence, and appropriateness, learners are able to organize their speech at discourse level and maintain the flow of conversation.
Lexical phrases are easy to acquire for two reasons.
First, they occur very frequently. High frequency provides natural recycling of such frames. Second, these formulas are context-bound and have situational meaning associated with them. Frequency of occurrence and context association make lexical phrases highly memorable for learners and easy to pick up. Stored as units, they are easily retrievable, highly accessible without the need for analysis by the rules of syntax.