I can help you practice your english :) message me if you want to talk. 

As a native speaker of spanish, inverted sentences are quite common in spanish. Both " El verano esta llegando " and " Esta llegando el verano " mean the same thing but sometimes there used differently. "El verano esta llegando" is used to tell someone that the summer is arriving. However, " Esta llegando el verano " is mostly used when asking someone if summer is arriving , though its rarely used to tell somebody that summer is arriving. It basically means " Is the summer arriving? " So not all inverted sentences will work out the same. Dont worry so much about it though, Its not a big grammar difference to it really...just know that it can be used both ways :) Also " El verano va llegando " is also correct. It is used as " The summer is going to arrive " Hoped I helped :) If you need more help in your spanish, I will gladly teach you more :) Just message me.

The difference is mainly the vocabulary. Also some words are spelled differently. Words ending in -or in american english would end in -our in british english. For example, "Color " would be " Colour " in Britain. Vocabulary would be similar but not completely different. For example, " Airplane " in America would be " Aeroplane " in Britain Dont worry about trying to learn both because they are both the same language, though there just used differently. Hope I helped.