The pronouns of Ido were revised to make them more acoustically distinct than those of Esperanto, which all end in "i". Especially the singular and plural first-person pronouns "mi" and "ni" may be difficult to distinguish in a noisy environment, so Ido has "me" and "ni" instead. Ido also distinguishes between intimate ("tu") and formal ("vu") second-person singular pronouns as well as plural second-person pronouns ("vi") not marked for intimacy. Furthermore, Ido has a pan-gender third-person pronoun "lu" (it can mean "he", "she", or "it", depending on the context) in addition to its masculine ("il"), feminine ("el"), and neuter ("ol") third-person pronouns.