Knowledge of them comes not only from language, but also from archaeology and archaeo-genetics. They were a group of loosely related peoples ancestral to the Bronze Age Indo-Europeans.
n ɑ l ɪ d̠ʒ WORD_BOUNDARY ʌ v WORD_BOUNDARY ð ɛ m WORD_BOUNDARY k ʌ m z WORD_BOUNDARY n ɑ t WORD_BOUNDARY oʊ n l i WORD_BOUNDARY f ɹ ʌ m WORD_BOUNDARY l æ ŋ ɡ w ɪ d̠ʒ WORD_BOUNDARY b ʌ t WORD_BOUNDARY ɔ l s oʊ WORD_BOUNDARY f ɹ ʌ m WORD_BOUNDARY ɑ ɹ k iː ɑ l ə d̠ʒ i WORD_BOUNDARY æ n d WORD_BOUNDARY ɑ ɹ k iː oʊ d̠ʒ ɪ n ɛ t ɪ k s WORD_BOUNDARY ð eɪ WORD_BOUNDARY w ɜː ɹ WORD_BOUNDARY ʌ WORD_BOUNDARY ɡ ɹ uː p WORD_BOUNDARY ʌ v WORD_BOUNDARY l uː s l i WORD_BOUNDARY ɹ ɪ l eɪ t ɪ d WORD_BOUNDARY p iː p ə l z WORD_BOUNDARY æ n s ɛ s t ɹ ə l WORD_BOUNDARY t ə WORD_BOUNDARY ð ə WORD_BOUNDARY b ɹ ɑ n z WORD_BOUNDARY eɪ d̠ʒ WORD_BOUNDARY ɪ n d oʊ j ʊ ɹ ɹ ə p iə n z WORD_BOUNDARY