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:

earlier philosophers whose work influenced the enlightenment included bacon, descartes, locke, and spinoza. the major figures of the enlightenment included beccaria, diderot, hume, kant, montesquieu, rousseau, adam smith, and voltaire. it spread the ideas of the enlightenment across europe and beyond.