If Scots is a separate language, it only became so in the last couple of hundred years. Starting from Old English, it lost the gender and concordance structure in the same way that English did. Sentence structure is the same in Scots and English. Differences are almost entirely in pronunciation and vocabulary.

One main difference is that, along with many northern English dialects, the vowel shift that happened from late Middle English to Modern English was less drastic. Another is the retention of guttural fricatives (ch as in 'loch', nicht for night etc.)

The spelling of English became standardised before modern pronunciation was fully developed, which means that the spelling often represents Scots better than English.