Technologies used for the study of speech are classified here into non-intrusive and intrusive. The paper informs on current non-intrusive technologies that are used for linguistic investigations of the speech signal, both phonological and phonetic. Providing a point of reference, the review covers existing technological advances in language research methodology for normal and disordered speech, cutting across boundaries of sub-fields: child vs. adult; first, second, or bilingual; standard or dialectal. The indispensability of such technologies for investigating linguistic aspects of speech is evident in an application that uses CLAN to manage and perform phonological and computational analysis of a bilingual child's dense speech data, longitudinally over 17 months of phonological development in Greek/English. Backed by acoustic analysis using Praat, developmental results on the child's labio-velar approximant in English are also given.