Linguistics in general, and Indo-European linguistics in particular, arose with the comparison of the lexicon, grammar, and texts of older languages. A group of nineteenth century scholars now known as the Neogrammarians formulated rules of sound correspondence that led to the view that "laws" of sound change are nearly as regular a phenomenon in language as the law of gravity is in the physical world.
Indo-European (IE) phonology has now evolved to include identification of phonemic segments, root structure, and hypotheses concerning laryngeal and glottalic consonants.
Now as in the earliest years of linguistics, the lexicon is fundamental. Here it is the focus of three major sections: the Semantic Fields pages, the PIE Roots pages [under construction], and the pages relating to PIE Phonemes.
See also: Language Classification