By speech and signals.
There are no primitive languages. All human speech is fully developed. That is why it is impossible to know for certain how language arose.
The most primitive form of human speech is believed to be nonverbal gestures, facial expressions, and vocalizations that conveyed basic emotions, needs, and intentions. These early forms of communication likely evolved into more complex languages over time.
part of speech
The part of speech for this particular word is a noun.
adverb
what part of speech is beneath
The part of speech for "answer" is a noun.
The part of speech for "explicit" is an adjective.
The part of speech for "unfamiliar" is an adjective.
The part of speech for "indefinite" is an adjective.
The part of speech for "lecturer" is a noun.