Accidentally came across this. There are few studies concerning children with CAS and suspected motor speech difficulties. Worth to read.
* A Proposed model for identification of childhood apraxia of speech in young children.* Using the Syllable Repetition Task to reveal underlying speech processes in childhood apraxia of speech* Emergent literacy skills in English-speaking preschoolers with suspected childhood apraxia of speech: A pilot study* Wee Words: A Parent-focused group program for young children with suspected motor speech difficulties