The aim of this study was to evaluate the influence of sublexical frequencies on the speech production of patients with apraxia of speech and patients with a phonological disorder. Recent studies have discussed syllable frequency as an important parameter which influences phonetically and / or phonologically disturbed speech. In the current investigation frequencies for the units syllable, phoneme, biphoneme, onset and rhyme were evaluated. The focus of our analysis was how the frequencies of the target units relate to those of the units realised by the patients. The results are discussed with regard to the pathomechanisms underlying of apraxia of speech and phonological impairment
