Silozi came into existence in the early 1800s when Sikololo speakers (Makololo) from South Africa came in contact with the Siluyana speakers (Luyi) in Barotseland. Today the language is spoken by over 700 000 people in Zambia, Namibia, Botswana, Angola and Zimbabwe collectively. Of the wealth of scholarship on the Malozi and their language, most focused on development and structure. Silozi dialect variation is yet to be explored in depth. This is a study of dialect variation in cross-border Silozi. The focus is on the lexicon and the morphosyntactic structures of the Silozi varieties spoken in the towns of Katima Mulilo (Namibia) and Mongu (Zambia). As an example of mixed-methods research, the data collection was conducted using the language documentation and description approach (see Lüpke, 2010; Himmelman, 1998). The data comprised of lexicon and sample sentences elicited via structured interviews from 70 participants. In addition, metalinguistic questions were used to collect information on essential language use patterns during data analysis. The findings confirmed that Silozi is the official language in Katima Mulilo, but Chisubiya and Chifwe are the dominant lingua francas. Contrastingly, in Mongu, Silozi is the main Bantu language, with others spoken minimally. A consequence of this is that the Katima Mulilo variety contained more lexical borrowings from other Bantu languages compared to Mongu. However, both varieties borrowed more lexicon from English than from the Bantu languages. Morphosyntactically, the Katima Mulilo variety contains grammatical features from Chisubiya that are not present in the Mongu variety. Chisubiya plays a central role in the differences that emerge between the two varieties. Overall, the Mongu variety appeared to be more stable and less susceptible to change. This thesis thus illustrates that there is nuanced variation in cross-border Silozi. Language contact and migration are shown to have been significant factors in ongoing language change in cross-border dialects.

Until very recently language development research classified the language learner as belonging to one of two discrete groups – monolingual or bilingual. This thesis explores the hypothesis that this is an insufficient description of language input and that there are sub-groups within the monolingual category based on the phonological variability of their exposure that could be considered akin to that of bilingual toddlers. For some monolingual toddlers, classified as monodialectal, their language exposure is generally consistent, because both of their parents speak the dialect of the local area. Yet for other toddlers, classified as multidialectal, the language environment is more variable, because at least one of their parents speaks with a dialect that differs from the local area. It is considered that by testing this group of multidialectal toddlers it will be possible to explore the effect of variability on language development and how increased variability in the bilingual linguistic environment might be influencing aspects of language development. This thesis approaches the influence of variability from three areas of interest: phonetic specificity of familiar words using a mispronunciation paradigm (Experiments 1 and 2), target recognition of naturally occurring pronunciation alternatives (Experiments 3 and 4) and use of the Mutual Exclusivity strategy in novel word learning (Experiment 5). Results show that there are differences between the two dialect groups (monodialectal and multidialectal) in a mispronunciation detection task but that toddlers perform similarly with naturally occurring pronunciation alternatives and in their application of the Mutual Exclusivity strategy. This programme of work highlights that there is an influence of linguistic variability on aspects of language development, justifying the parallel between bilingualism and multidialectalism.

Research on the dialects of English spoken within the United States shows variation regarding lexical, morphological, syntactic, and phonological features. Previous research has tended to focus on one linguistic variable at a time with variation. To incorporate multiple variables in the same analysis, this thesis uses a latent class analysis to perform a cluster analysis on results from the Harvard Dialect Survey (2003) in order to investigate what phonetic variables from the Harvard Dialect Survey are most closely associated with each dialect. This thesis also looks at how closely the latent class analysis results correspond to the Atlas of North America (Labov, Ash & Boberg, 2005b) and how well the results correspond to Joshua Katz's heat maps (Business Insider, 2013; Byrne, 2013; Huffington Post, 2013; The Atlantic, 2013). The results from the Harvard Dialect Survey generally parallel the findings of the Linguistic Atlas of North American English, providing support for six basic dialects of American English. The variables with the highest probability of occurring in the North dialect are ‘pajamas: /æ/’, ‘coupon: /ju:/’, ‘Monday, Friday: /e:/’ ‘Florida: /ɔ/’, and ‘caramel: 2 syllables’. For the South dialect, the top variables are ‘handkerchief: /ɪ/’, ‘lawyer: /ɒ/’, ‘pajamas: /ɑ/’, and ‘poem’ as 2 syllables. The top variables in the West dialect include ‘pajamas: /ɑ/’, ‘Florida: /ɔ/’, ‘Monday, Friday: /e:/’, ‘handkerchief: /ɪ/’, and ‘lawyer: /ɔj/’. For the New England dialect, they are ‘Monday, Friday: /e:/’, ‘route: /ru:t/’, ‘caramel: 3 syllables’, ‘mayonnaise: /ejɑ/’, and ‘lawyer: /ɔj/’. The top variables for the Midland dialect are ‘pajamas: /æ/’, ‘coupon: /u:/’, ‘Monday, Friday: /e:/’, ‘Florida: /ɔ/’, and ‘lawyer: /ɔj/’ and for New York City and the Mid-Atlantic States, they are ‘handkerchief: /ɪ/’, ‘Monday, Friday: /e:/’, ‘pajamas: /ɑ/’, ‘been: /ɪ/’, ‘route: /ru:t/’, ‘lawyer: /ɔj/’, and ‘coupon: /u:/’. One major discrepancy between the results from the latent class analysis and the linguistic atlas is the region of the low back merger. In the latent class analysis, the North dialect has a low probability of the ‘cot/caught’ low back vowel distinction, whereas the linguistic atlas found this to be a salent variable of the North dialect. In conclusion, these results show that the latent class analysis corresponds with current research, as well as adding additional information with multiple variables.