Stuttering or Stammering
If your child has difficulty speaking and is repeating sounds or hesitating on certain words or syllables then they may have a stuttering problem. Many children experience periods of normal disfluency (i - y) when learning to talk. Sometimes this is due to the child learning to use language in new ways. Generally it will come and go.
Someone who stutters might repeat a sound or a syllable, especially at the beginning of the word, such as "li- li- like." At other times it can be a prolongation of a sound such as "ssssssee." Or in other cases it involves complete stoppages of speech.