Exactly...
You're born with the capacity to learn language. And any language skills you aquire are from your surroundings after birth... if no one in your household talks, you simply won't learn to speak yourself. If people around you communicate on a really limited level, that is also going to affect your language development, slowing it down significantly... seriously how many kids who are treated as having learning disabilities are just the victims of parents who never really talked to them much, or used very poor language themselves? Wow this is getting off subject ima shut up now!

I'm thinking, as a SPECIES, when humans first started communicating verbally.