Why are British, Australian and New Zealand Sign Languages considered different languages not dialects of British Sign Language?

Deaf communities in the United Kingdom, Australia and New Zealand use British, Australian and New Zealand Sign Languages respectively. Many publications explain the similarities between the languages, as their historical backgrounds are closely related. The three sign languages have one common parent language – British Sign Language. Therefore, it is understandable why there are many similarities between the sign languages and why they are often thought to be dialects of one language instead of being three different languages. Nevertheless, three different sign languages have emerged from their common ancestor despite their close resemblance.

As sign language phonology is a rather new field of study, there is a lack of literature on the topic. This prompted the idea of conducting phonological analysis on different signs from British, Australian and New Zealand Sign Languages. This research project intended to research why the three sign languages are considered different languages not dialects of one language. This was achieved by conducting phonological analysis on five sets of words and comparing the phonological differences between the three sign languages and why these variations have appeared.

I have used Stokoe’s notation system to annotate the signs and compare their varying parts. I have found that despite having similarities, the signs differ significantly on their phonological level. Various publications on defining language and dialect were used to conclude the reasons for the variances. In addition, knowledge on the historical background of the languages helped to reason the historical lexical and phonological differences.

This project proves statements from numerous authors why the three sign languages and their lexicon or phonology differ despite having only recently separated from each other. Even though British, Australian and New Zealand Sign Languages have phonological similarities, they are still considered different languages as they are not completely mutually intelligible.