English has borrowed lots of words from other languages. This usually happens when there wasn’t already a word for it in English. Some examples of English words that are not really English are: iceberg, algebra, ski and ghoul.
Once upon a time oranges were called noranges. Over time, the ‘n’ sound moved from the beginning of the word ‘orange’ and attached itself to the end of the word ‘a’, so a norange became an orange. The posh word for this happening is metanalysis and the evidence is in the Spanish word for orange (naranja). Other words this has happened to are apron and adder. Sometimes it happens the other way round to with the ‘n’ moving from the end of ‘an’ to the start of the next word. Eg ‘a nickname’ used to be ‘an ekename’.