Acquired apraxia of speech is a neurogenic speech disorder that is characterized by
- erroneous production of speech sounds
- reduced rate of speech
- increased time in transitioning between sounds, syllables, and words
- disordered prosody

May be accompanied by
- articulatory groping
- difficulty initiating speech
- increasing number of sound errors with increasing word length
- motoric perseverations

Severity ranges from a complete inability to speak to minimal disruptions in speech production

Slow speech rate:
         Lengthened segments (vowels and/or consonants)
         Lengthened intersegment durations (between sounds, syllables, words,
                   phrases: possibly filled with intrusive schwa)
Sound distortions (including consonants and vowels)
Distorted sound substitutions
Errors are relatively consistent in type (e.g. substitution, omission, distortion) and location in repeated
          utterances
Prosodic Abnormalities

Articulatory groping: audible and/or visible and probably disordered relative to the target
Perseverative errors (perseverations of movement patterns)
Increasing errors with increasing word length
Speech initiation difficulties
Awareness of errors
Automatic speech better than propositional speech
Islands of error free speech

Reference:

McNeil, M.R., Robin, D. & Schmidt, R. (1997). Apraxia of speech: Definition, differentiation and treatment. (311-344).  In: M.R. McNeil (Ed.), Clinical Management of Sensorimotor Speech Disorders. New York: Thieme Medical Publishers.

For more information:

National Institute on Deafness and Other Communication Disorders
American Speech-Language-Hearing Association
National Stroke Association
National Aphasia Association