Complex sentence: English is spoken worldwide, and while the Standard English grammar that is generally taught in schools around the world may vary only slightly, if at all, in actual usage, the English of one country is not always the English of another.
Split into simpler sentences: English is spoken worldwide, and while the Standard English grammar that is generally taught in schools around the world may vary only slightly, if at all. In actual usage, the English of one country is not always the English of another.