From Bulbapedia, the community-driven Pokémon encyclopedia.

A dub of the Pokémon anime is a version which has voices recorded in a different language than the original Japanese. By some definitions of the word, the original Japanese recording can also be considered a dub, but fans almost exclusively use the word to refer recordings in other languages, and refer to the Japanese recording as "the original" or "raw" version.

Production

The English dub was produced by 4Kids Entertainment and TAJ Productions from seasons one through six. Seasons seven and eight were produced solely by 4Kids Entertainment. Seasons nine and ten were produced by Pokémon USA and TAJ Productions. Presently, the dub is produced by Pokémon USA with DuArt.

Criticisms

The dub has been the target of criticism and controversy throughout it's history. Despite these criticisms, the English dub is well received, and has many viewers, some even prefering it over the original Japanese anime. Many would like to see DVDs containing the original Japanese version with subtitles, but that has yet to happen.