In the past 1500 years, the indigenous languages of the British Isles and Ireland shifted, typologically speaking, from a predominant syntheticity to a predominant analycity. This shift occurred across language families, as English and Scots are commonly classed as Germanic languages, while Irish, Scottish Gaelic, Manx, Welsh, Cornish and Breton are classed as Insular Celtic languages. Among these languages, Late British, the forerunner of Welsh, Cornish and Breton, historically headed the shift by shedding nearly all of its inflections in the NP (syncretism). This shedding is believed to have occurred between c. 400 and 600 A.D. Today, English and Scots are more analytical than Welsh and Breton, because of their dramatic loss of nearly all of their inflections both in the NP and the VP. Irish and Scottish Gaelic are still somewhat more synthetic than the other Insular languages. In the spoken language, however, they are closely following suit. This shared development entailed a thorough restructuring of the morphology and syntax of the respective languages and led to convergence phenomena which have been hardly studied so far.

Salient aspects of this shared development of the Insular languages are currently under research by the member of the research team. Their research results promise a closer understanding of the present day analyticity of the English language in the context of the other indigenous languages of the British Isles and Ireland.