Synchronic and diachronic aspects of the English how come construction: An HPSG analysis

The expression how come is analogous to why in many grammatical aspects, yet displays various distinct properties. There have been several theoretical attempts to deal with the how come construction in present-day American English, but few are successful in capturing the full range of variation observed in attested data. We investigate synchronic and diachronic grammatical properties of the construction, using data from corpora such as COCA (Corpus of Contemporary American English), COHA (Corpus of Historical American English) and EEBO (Early English Books Online). Analysis of 13,500+ corpus instances reveals that unlike its historical variants how comes/came, the modern how come underwent grammatical constructionalization and emerged as a lexical unit. Our corpus investigation also motivates a lexicalist HPSG analysis that can account for the observed synchronic and diachronic properties of the construction in a systematic way.