Diagnosis involves testing and evaluation during which it is determined if the scores/performance are "substantially below" developmental expectations and if they "significantly" interfere with academic achievement, social interactions, and daily living. This assessment may also determine if the characteristic is deviant or delayed. Therefore, it may be possible for an individual to have communication challenges but not meet the criteria of being "substantially below" criteria of the DSM IV-TR. The DSM diagnoses do not comprise a complete list of all communication disorders, for example, auditory processing disorder is not classified under the DSM or ICD-10. The following diagnoses are included as communication disorders:

Expressive language disorder – characterized by difficulty expressing oneself beyond simple sentences and a limited vocabulary. Individuals can better understand than use language; they may have a lot to say, but have more difficulty organizing and retrieving the words than expected for their developmental stage. Mixed receptive-expressive language disorder – problems comprehending the commands of others. Stuttering – a speech disorder characterized by a break in fluency, where sounds, syllables, or words may be repeated or prolonged. Phonological disorder – a speech sound disorder characterized by problems in making patterns of sound errors (e.g., "dat" for "that"). Communication disorder NOS (not otherwise specified) – the DSM-IV diagnosis in which disorders that do not meet the specific criteria for the disorder listed above may be classified. DSM-5
The DSM-5 diagnoses for communication disorders completely rework the ones stated above.
Unspecified communication disorder – for those who have symptoms of a communication disorder but who do not meet all criteria, and whose symptoms cause distress or impairment. Examples
Examples of disorders that may include or create challenges in language and communication and/or may co-occur with the above disorders:

autism spectrum disorders - autistic disorder, pervasive developmental disorder not otherwise specified (PDDNOS), and Asperger disorder – developmental disorders that affect the brains normal development of social and communication skills. expressive language disorder – affects speaking and understanding where there is no delay in non-verbal intelligence. mixed receptive-expressive language disorder – affects speaking, understanding, reading and writing where there is no delay in non-verbal intelligence. specific language impairment – a language disorder that delays the mastery of language skills in children who have no hearing loss or other developmental delays. SLI is also called developmental language disorder, language delay, or developmental dysphasia. Sensory impairments
Blindness – A link between communication skills and visual impairment with children who are blind is currently being investigated. Deafness/frequent ear infections – Trouble with hearing during language acquisition may lead to spoken language problems. Children with frequent ear infections may temporarily develop problems pronouncing words correctly. Some of the above communication disorders can occur with people who use sign language. The inability to hear is not in itself a communication disorder. Aphasia
Aphasia is loss of the ability to produce or comprehend language. There are acute aphasias which result from stroke or brain injury, and primary progressive aphasias caused by progressive illnesses such as dementia.