Although any root could theoretically be used to create a noun or a verb, there is evidence for the existence of distinct noun and verb roots, which behave in different ways.
ɔːlðˈoʊ ˌɛni ɹˈuːt kʊd θiəɹˈɛɾɪkli biː jˈuːzd tə kɹiːˈeɪt ɐ nˈaʊn ɔːɹ ɐ vˈɜːb, ðɛɹ ɪz ˈɛvɪdəns fɚðɪ ɛɡzˈɪstəns ʌv dɪstˈɪŋkt nˈaʊn ænd vˈɜːb ɹˈuːts, wˌɪtʃ bᵻhˈeɪv ɪn dˈɪfɹənt wˈeɪz.