Complex sentence: The corpus was restricted to just British English and was not extended to cover World Englishes, partly because a significant portion of the cost of the project was being funded by the British government which was logically interested in supporting documentation of its own linguistic variety.
Split into simpler sentences: The corpus was restricted to just British English, and was not extended to cover World Englishes. This was partly because a significant portion of the cost of the project was being funded by the British government which was logically interested in supporting documentation of its own linguistic variety.