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This thesis investigates the phonetics and phonology of geminate consonants in Libyan Arabic (LA). In addition to lexically contrastive geminates ‘true geminates’, LA has two types of phonologically derived geminate: ‘fake geminates’, which are formed as a combination of two identical consonants at the juncture of a word or a morpheme, and ‘assimilatory geminates’, which are the result of total assimilation. This study examines the effect of the phonological status of a geminate on the phonetic realization to ascertain whether underlying differences are reflected in phonetic dissimilarity. In particular, it investigates two questions: what are the acoustic and articulatory differences between singletons and lexical geminates; and are there any acoustic or articulatory differences between the three types of geminates. To answer these questions, two phonetic studies were conducted: one acoustic and one articulatory (EPG). Trisyllabic minimal or near minimal utterances containing the sonorant sounds /l, m, n, r/ were considered. Native speakers of LA were recorded reading word-lists containing medial singleton and geminate consonants preceded by short and long vowels. The acoustic study investigated both durational and non-durational parameters. The articulatory study investigated spatial and spatio-temporal (dynamic) parameters. The results provide evidence that the singleton-geminate contrasts as well as the three geminate types are phonetically distinct from each other when considering both the acoustic and articulatory correlates together. The acoustic results confirm that the primary correlate which distinguishes singletons from geminates in LA is duration. The duration of the preceding vowels gives evidence in support of temporal compensation as one of the correlates of geminates. The comparison between the three types of geminates shows that they all display similar durational and non-durational values. However, the behaviour of short and long vowels preceding assimilatory geminates is suggestive and may contribute to the phonetic distinction between these geminates and the other geminate types. The articulatory results show that the singleton and geminate consonants in LA are different in their articulatory configurations. Fake geminates are also found to be distinct both spatially and dynamically from true and assimilatory geminates, which show similar articulatory patterns. The theoretical implications of these results for the general issue of geminate behavior are discussed.

The main goal of this thesis is to provide a description of the articulatory and temporal interaction between stops spanning the word boundary in the four sequence types VC#CV, VC#CCV, VCC#CV, and VCC#CCV in Tripolitanian Libyan Arabic. A general aim of the study is to contribute to the Phonetic description of Libyan Arabic and to provide a better understanding of speech production and the temporal organisation of articulatory gestures. One of the principal objectives of this study is to investigate what effect an increase in the number of stops in a sequence will have on the timing of stop gestures. Furthermore, the study aims to identify the different patterns of gestural coordination and the types of inter-consonantal intervals occurring between stops in the four sequence types. Another aim of the study is to investigate the nature of the resulting inter-consonantal intervals occurring between these stops in order to understand the patterns of epenthesis. Factors affecting gestural coordination such as the order of place of articulation of stops and speech rate are also an objective of this study. Voice assimilation across the word boundary is also investigated in addition to the influence of inter-consonantal intervals on the process. The study adopts Articulatory Phonology as a theoretical framework to carry out the investigations. The data was collected through recordings of participants’ speech and was subjected to EPG and acoustic analysis. Ten native speakers of Tripolitanian Libyan Arabic took part in the acoustic part of the study. Two of the speakers also took part in the EPG part of the study. Results show that the effect of the number of stops in a sequence on gestural timing is not limited to within syllable-initial and final clusters but also spreads across the word boundary. The timing of syllable-final and syllable-initial stops decreases as a result of the increase in the number of stops across the word boundary. The results also show that the timing of syllable-final clusters is more variable than syllable-initial clusters in across word boundary sequences. Different sequences types exhibit different degrees of gestural coordination and epenthesis patterns between adjacent stops. Inter-consonantal intervals occurring as a result of lag durations between adjacent stop gestures fall into two types. The first type are typical of transitional excrescent vowels with a mean duration ranging from 14ms-20ms and their voice values exhibit more variation as a result of the voice context in which they occur. Inter-consonantal intervals of the second type are typical of epenthetic vowels with a mean duration ranging from 43ms-51ms and are usually specified as voiced. The patterns of epenthesis also show that Tripolitanian Libyan Arabic belongs to the VC type of languages where sequences of three stops CCC are broken up by epenthesis occurring between C1 and C2 of the sequence. Statistical tests show a significant effect for order place of articulation on gestural coordination across the word boundary in TLA in the C#C sequence where gestures are more closely coordinated in the coronal-dorsal order. Regressive voice assimilation is more frequent and the voice context of the stops involved plays a major role in determining the direction of voice assimilation spreading. Progressive voice assimilation is limited to the –V+V voice context and whereas regressive assimilation of voicelessness occurs in both. Furthermore, excrescent vowels are found to be transparent to voice assimilation and are dependent on the voicing of the trigger segment. On the other hand, epenthetic vowels block voice assimilation and are more dependent usually specified as voiced.

This study uses acoustic, electropalatographic and laryngographic data to investigate articulatory timing and the timing of voicing of single stops and two-stop consonant clusters in Tripolitanian Libyan Arabic. The theoretical framework which has been adopted in this investigation is based on Articulatory Phonology. An acoustic approach is also employed in this study to measure the duration of segments and overlap in clusters. Another objective of this research is to determine whether syllable position, place of articulation, including articulation sequence, the morphological structure, gender of the speaker and articulation rate will have an influence on the gestural coordination and the timing of voicing of Tripolitanian Libyan Arabic stops. Fourteen native speakers of Tripolitanian Libyan Arabic produced fifty-eight mostly monosyllabic words that contain seven syllable-initial single stops, seven syllable-final single stops, twenty-seven syllable-initial two-stop clusters and seventeen syllable-final two-stop clusters in normal, fast and slow articulation rate. One speaker was recorded using Electropalatography and Laryngography. Measurements include duration of the hold phase of the stops, the duration of overlap/delay between two adjacent consonantal closures, the timing and duration of the voicing during the hold phase and the duration of VOT. Statistical results show significant influence of syllable position, place of articulation, gender and speaking rate on the gestural coordination of two-stop clusters. In syllable-initial position, the pattern of coordination is characterised by an overlap between the two consonantal closures or by a short delay as a result of the release of the first stop. In syllable-final position, the pattern of coordination of two consonantal gestures is marked by a less cohesive coordination leading to the existence of an epenthetic vowel. These patterns of coordination varied as a function of place of articulation, gender of the speaker and the rate of articulation. Clusters with lingual stops are less overlapped compared to clusters containing bilabial stops. Male speakers produced longer hold phase durations and longer inter-consonantal intervals in comparison with female speakers. While in faster articulation rates the two consonantal gestures were reduced in duration and exhibited more gestural overlap, slow articulation rate resulted in the opposite outcome. Results of the influences of articulation sequence and morphological structure of the cluster were less evident. Finally, the duration of voice onset time and the timing and duration of voicing during the hold phase varied as a function of syllable position, place of articulation and articulation rate, with more voicing in syllable-final single stops than syllable-initial and an increase in voicing by the increase in articulation rate, and the opposite pattern is evident in slow articulation rate. The duration of VOT becomes longer as the place of articulation moves back and shorter when the articulation rate is increased. In slow speaking rate, VOT is longer.