I would like to suggest adding the Scots language as an option. There is a distinction between Scottish English, which is what the category "English (Scots)" should be used for, and the Scots language, which is a distinct language from English (and Scottish Gaelic).
The UK government recognizes Scots as a regional language under the European Charter for Regional and Minority Languages. Scots is also one of the three languages, along with Scottish Gaelic and English, recognized by the Scottish Parliament. We also just had Harry Potter and the Philosopher's Stone translated into Scots last year!
Just in the last couple days, I've translated seven songs into Scots and two songs from Scots to English. Furthermore, from what I've seen, the majority of songs in the current "English (Scots)" category are actually in Scots language: not English. They would therefore be more properly placed in a new, separate "Scots" category.
To reiterate, the new language category, if made, would simply read: "Scots."
Thanks for the consideration.