Board Thread:General Discussion/@comment-25563055-20141024231726/@comment-5051846-20160524161830

@NeevaDash: Oh, Cyber Diva is generally considered to be higher quality than Gumi English. Gumi English is popular for her pleasent tone of voice, but she has issues with choppiness which makes her significantly harder to use. Of course, which you prefer depends on your personal preference. (* ´ v ` )ﾉ

Vocaloid was originally developed in Spain, you can find out more on it's development here. You are correct in that the Japanese language was probably the first Vocaloid was programmed for. However, the first Vocaloids were English, so the software has always been designed with English in mind. When MEIKO was released, you could only use Vocaloid in English, there was no Japanese language setting.

My personal point of view is that Engloids are not as popular for 2 main reasons:

1. Marketing 

Japanese Vocaloids caught on because their anime avatars appealed strongly to the online otaku audience. Anime isn't as popular in the West; we've yet to find the perfect way to advertise Vocaloids for the English market.

2. Pronunciation

Engloids sound weird. 'Weirdness' is hard to define, but their pronunciation has an inhuman quality which isn't widely appealing. This is partly due to the fact that English is much more complex to synthesis than Japanese.