In this thesis, the long-standing problem in Indo-Iranian linguistics whether or not to reconstruct a phoneme /l/ for Proto-Indo-Iranian is examined in detail. After a brief status quaestionis, the...Show moreIn this thesis, the long-standing problem in Indo-Iranian linguistics whether or not to reconstruct a phoneme /l/ for Proto-Indo-Iranian is examined in detail. After a brief status quaestionis, the etymology of all words with a phoneme /l/ in Ṛgvedic Sanskrit is scrutinized to see which words are likely borrowed from substratum languages and which go back to Proto-Indo-Iranian. Secondly, the problem is studied from a synchronic perspective. On the basis of the distribution of /l/ and /r/ in the different books of the Ṛgveda, it is argued that both diachronic and diatopic factors play a role, i.e. that generally speaking later books and books written in more eastern parts of India have a higher frequency of words with /l/. Finally, the diastratic component is taken into consideration as it is shown on the basis of a semantic analysis and with attention to female speech that /l/ was part of the lower registers of Vedic Sanskrit. This evidence combined, it is argued in the conclusion that /l/ gradually lost its function as a phoneme in Proto-Indo-Iranian, a process that was completed in Old Iranian and Mitanni Indo-Aryan with the complete loss of a phoneme /l/. This, however, was interrupted in Old Indo-Aryan, due to a profound influx of substratum words with the phoneme /l/.Show less