Here are the main differences between the US and UK Little Reader English Curricula:
Voices (pronunciations) are recorded by native speakers with either an American (US) or British (UK) accent.
Different vocabulary words in some instances. For example, "stroller," "pants" and "elevator" are used in the US curriculum, while "push chair," "trousers" and "lift" are used in the UK curriculum.
If you are living in a country where most residents use American English, then perhaps the US Curriculum would be most applicable for your child. However, we do not "restrict" nor "require" anyone into getting either US or UK content simply because of one's country of residence. This option is available for everyone, and if you like you may take a free trial first and see which one works best for you and your child.