babbling

Short definition from Wiktionary

Noun

1. 1
   a stage in child language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words
2. 2
   sounds produced by infant during the babbling period
3. 3
   Idle senseless talk; prattle.
4. 4
   A confused murmur, as of a stream.

Adjective

1. 1
   That babbles.

Verb

1. 1
   present participle and gerund of babble