1. A method comprising: receiving a candidate lexical kernel unit comprising a word token sequence that includes two or more words; retrieving domain terms that contain the two or more words from a terminology resource file of domain terms associated with a domain; analyzing the candidate lexical kernel unit and the retrieved domain terms to determine whether the candidate lexical kernel unit satisfies specified criteria for use as a building block by a natural-language processing (NLP) tool for building larger lexical units in the domain, each of the larger lexical units including a greater number of words than the candidate lexical kernel unit; identifying the candidate lexical kernel unit as a lexical kernel unit based on determining that the candidate lexical kernel unit satisfies the specified criteria; and outputting the lexical kernel unit to a domain-specific lexical kernel unit file for input to the NLP tool.