The earliest stage of speech development is called the

babbling stage

Explanation:

Babbling stage is the the primary stage of language acquisition, which usually occurs around ages 3-4 months. During this stage, children utter articulate but unrelated sounds. This is a stage where babies attempt to imitate the sounds that they hear, often with no success. No recognizable words are produced, but this is a positive step towards forming words, which happens around 12 months.

babbling is the correct answer.

Explanation:

the answer is true .

the telephone is the answer