Others suggest specific sounds or words, but invite alternatives if the child cannot follow the specific vocal pattern. Both understanding and expressing the rules of a language are involved in language complexity. Songs that ask a child to follow a story line or series of commands are more challenging than songs that are created from a series of sounds without specific meaning. When language demands are simple, vocalization and sound play are easier. Songs that come from the emotions and are driven more by affect than by cognitive thought are usually easiest.
Children laugh, giggle, sneeze, cry, and fuss long before they understand how to make other sounds.
Imitation of animal and environmental sounds is also at the easy level of sound production. Later, children sing songs with repetition of numbers and letters. Although these are more language-based, they are an automatic series of words that do not require an understanding of the meaning behind the words. Imitation of a series of nonsense syllables falls into the same general category. The child imitates a specific sound pattern, but there is little or no meaning behind it.