唠 (láo) is a bound morpheme that only appears in compound words related to talking. The most common compound is 唠叨 (láodao), meaning 'to chatter, to nag'. Another is 唠嗑 (làokē), a colloquial term for 'to chat'. It has no independent meaning outside of these disyllabic words, so you never use it alone. Think of 唠 as the first syllable in a two-syllable talk-related verb.