In my never ending quest to get my clients' therapy covered (partially covered) by their insurance companies (which they should!), I have finally found codes that are actually accepted without a problem (most of the time).

Use the following * CPT CODES :
CPT 92506 may be used to report evaluation of speech, language, voice, communication, auditory processing, and/or aural rehabilitation status.
CPT 92507 may be used for the treatment of speech, language, voice, communication, and/or auditory processing disorder.
*These codes are considered comprehensive and therefore cover a broader range of diagnostic and therapeutic services.

The ICD-9 codes will vary according to your client's diagnosis. I use the following with success:
ICD-9 784.6 may be used for the treatment of a receptive/expressive language impairment.
ICD-9 784.69 may be used for the treatment of apraxia of speech or CAS (childhood apraxia of speech).

TIPS:

1. Always remember to obtain your client's reference number and put it on each bill beneath your client's name.
2. Always include your state licensure number, your ASHA certification number and your Tax I.D. on the bottom of each bill.
3. Always keep a copy of your bills and any correspondence you receive from your client's insurance company.

GOOD LUCK!