本文旨在比較台灣閩南語常人、弛緩型(flaccid dysarthrics)、與痙攣型(spastic dysarthrics)神經性構音障礙病患子音絕對及相對音長之差異，並探討此病態語音在了解說話運動系統之特徵以及了解語言產製過程上可能的暗示。 結果顯示神經性構音障礙病患的子音絕對音長顯著長於常人受試者，但兩組病患延長的型態並不相同。首先，弛緩型病患子音音長顯著長於痙攣型病患；再者，以子音的帶音與否、發音位置、發音方法這三個向度來看，弛緩型病患之子音音長展現了全面性的延長，而痙攣型病患則產生了選擇性的延長，其子音之延長，大多集中在有聲子音上，這些差異乃因兩組病人病理狀況不同所致。 另一個結果則顯示，雖然神經性構音障礙病患，在子音音長呈現了延長的狀況，但在子音間相對音長次序上，仍保持到某種程度的完好，可是，子音雖保持一定的次序，但彼此間音長的差值及比值卻也發生了改變。而子音在音節中的所佔比例卻又和正常人無異。 因此，本文推斷，在常人子音的產製上，是要求精確的絕對音長，而且子音間音長亦要保持一定的相對關係；但若因病變致使說話者無法同時兼顧二者時，說話者會選擇犧牲絕對音長，而仍保持子音音長間的相互關係。這可能是語言產製與感知的一些經濟原則(principles of economy)互動所導致的結果。此外，構音障礙病患表就子音在音節中的相對時長這個向度上，和常人無異，這可能是語言文法與生理限制二項因素互動所致。 / This study aims (1) to investigate the absolute and relative timing of consonant duration in Taiwanese neurogenic dysarthric speech by means of acoustic measurements, (2) and to explore their implication on the characteristics of motor system and on the status of timing control in speech production. The results show that absolute consonant duration in flaccid and spastic dysarthric speech are significantly longer than that in normal controls. However, the "lengthening" phenomena display different patterns in flaccid and spastic groups. First, for the patients with the same degree of muscular dysfunction, the flaccid dysarthrics lengthen the consonant duration significantly greater than the spastic ones do. Second, whereas absolute consonant duration in flaccid group shows overall lengthening regardless of voicing state, stricture type, and place of articulation, that in spastic group displays selective lengthening. Besides, though the absolute consonant duration is lengthened in dysarthric speech, the durational opposition between consonants is more or less distinct. However, only the durational ranking between consonants (external timing relation) is maintained in dysarthric, but the durational distance or ratio between consonants (internal timing relation) is modified. Relative timing of consonant duration, that is, the consonant-to-syllable ratio (cs-ratio) within a syllable remains intact in dysarthric speech even though the segmental duration is lengthened. Lengthened absolute consonant duration in dysarthric speech is accounted for by the neurological deficits and compensatory effects. Longer absolute consonant duration in flaccid than in spastic speech is attributed to slowness and weakness without spasticity of speech musculature in flaccid dysarthria. Overall lengthening of consonant duration in flaccid group results from the entirely-impaired cranial nerves innervating speech musculature, whereas selective lengthening of consonant in spastic group is ascribed to spasticity and the selective pattern as well as directionality of neuromuscular impairments in spastic dysarthria. The reserved durational ranking between consonants in dysarthric speech may result from the compromise of principles of economy in speech production and perception. The normal-like CS-ratios in dysarthric speech stem from the interaction between biological constraints and the grammar of a language. Based on the data collected from dysarthric speech, this study discusses the temporal variance as well as invariance in speech motor system and the status of timing in the grammar of a language. The importance of principles of economy in speech production and perception is also indicated.