Use of syntactic language is a unique characteristic of humans. Following the split of human line from chimpanzee line around six million years ago some individuals acquired genetic modifications that enabled certain linguistic abilities. Over time these mutations were fixed in the human population and currently enable modern human syntactic communication. Inevitably, in some modern individuals, language-critical genes regress to their ancestral functionality causing partial loss of language abilities. Population studies of individuals with language deficits reveal language phenotypes that may correspond to stages of language evolution. Previously, we discovered three distinct language-comprehension-phenotypes: 1) individuals in the command-language-comprehension-phenotype were limited to comprehension of simple commands; 2) the modifier-language-comprehension-phenotype showed additional comprehension of color, size, and number modifiers; 3) the most-advanced syntactic-language-comprehension-phenotype added comprehension of complex grammatical sentences 1. In this study we clustered language comprehension skills together with speech abilities in 55,000 individuals-with-language-deficits. We discovered four distinct phenotypes: 1) command-language-comprehension with no-expressive-language; 2) modifier-language-comprehension with single-word-expressive-language; 3) modifier-language-comprehension with single-sentence-expressive-language; 4) syntactic-language-comprehension with multi-sentence-expressive-language. These phenotypes may align with four distinct stages of language comprehension and speech co-evolution. Using homology between neurological mechanisms underlying language and stone-tools-manufacturing we deduce the chronology of language acquisition in our ancestors.