US/UK Englishes
Spelling differences
US -or, UK -our (color, colour)
US -ze, UK -se (analyze, analyse)
US -ize, UK -ise/-ize (recognize, recognise/recognize)
US -yze, UK -yse (analyze, analyse)
US -ense, UK -ence (some, e.g. license, licence)
US -ll, UK -l (fullfill, fulfill)
US -er, UK -re (center, centre)
US -og, UK -ogue (some, e.g. dialog, dialogue)
US -ck/k, UK -que (check, cheque)
US -dg, UK -dge (judgment, judgement)
Other: US jewelry, UK jewellery; US pajamas, UK pyjamas;
US program, UK programme; US traveling, UK travelling (et al.); US learned, UK learnt (complete list of irregular verbs by people at Georgia State University, USA).
More: Spelling differences 
Jeremy Smith's The American-British, British-American Dictionary: Explanation of Differences : spelling
