I'm not sure if this is entirely true, but I believe that after the commercial failure of KAITO Crypton tried a female Vocaloid character (in this case, Miku Hatsune) and she took the world by storm. Therefore, in order to keep on top, Crypton continued making female Vocaloids, adding some males to keep the balance.
yes
depends on which one you buy. Luka is bilingual and can sing very well in english., and all the vocaloids can sing in english, but you can barley understand them.
Appends are like updates for the Vocaloid. They are different voice types made to express the different emotions the Vocaloid may have.
Madonna
Madonna
there is a game based on vocaloids, but originally its a program.
Gackpoid does not have an official age and most VOCALOIDs don't.
Probably utauloids
There are a lot of VOCALOIDs. VOCALOIDs are now up to at least 45, and their are more than 60 voicebanks.
No. VOCALOIDs are not couples. VOCALOIDs do not have to deal with anime or couples. It's only a singing program.
yes
There is no any other VOCALOIDs. All vocals found in VOCALOID wikia are the original VOCALOIDs made buy actual music/recording companies. Haku Yowane, Akita Neru, and Hatsune Mikuo etc. are fanmade based of the VOCALOIDs voicebanks.
around $200
Utaloid is a subcategory of Vocaloid software, with an emphasis on Japanese-speaking virtual singers developed by a specific company. Vocaloid refers to a broader category of voice synthesizing software that can produce singing by inputting lyrics and melodies.
Every VOCALOIDs have diffrent prices. The cheapest VOCALOID is currently $40 dollars and the highest price is about $400. You can buy the VOCALOIDs in their company's website.
you can find most of it on youtube, and some on specialty sites - but most animes have no official english versions of their songs. most will be fan-made or vocaloids.
To me i think Vocaloids did