When to use - in Scottish words
When is it appropriate to use the dash because it seems that only the word now keeps it but others change?
Words that include a " - " will often include it in the dictionary. Example a-nis, a-mach, a-muigh.
A " - " is used when h is prefixed to a word, for example in the phrase "a h-uile duine."
When using a definite article that includes t , then the dash is used. For example, an t-each (the horse) or an t-sùil (the eye).
Unfortunately Duolingo doesn't include punctation on word blocks (so the course creators can't change this). If you are using word blocks for any of the examples above or other similar cases, there isn't going to be a " - " on any of the blocks.
That does make it confusing for learners to learn when the dash must be included. Also, even if it doesn't show up on the word blocks, if you have to include it when typing then the correct answer needs to have the dash.
One more confusing part is that Duolingo doesn't require perfect typing for a correct answer -- so you might leave the dash out of an answer and still get it correct.
I’m sorry it’s not completely clear what you’re asking....but I’ll try...
You could make notes when new words are presented (especially if they have specific punctuation or difficult spellings), then you will have a record of how each word is written, including any punctuation. Also, you can check in the ‘dictionary’ tab to see how each word you’ve learned should be written...you can find this by pressing the “ ... “ icon at the top (well, it’s at the top on the website...I don’t know where it is on the app, sorry :)
Hope this helps
In addition to the good explanations above, one reason for using the hyphen is to indicate where the stressed syllable lies. Unless otherwise indicated, the stressed syllable in Gaelic words is usually the first syllable (there are some exceptions, for example in loanwords such as telebhisean, buntàta, and in days of the week, Diluain, Dimàirt, etc.). A hyphen in words like a-mach, a-staigh, a-nis, a-rithist, mì-mhodail, co-dhiù, ma-thà, etc. tells you that the first syllable after the hyphen is the stressed syllable, rather than the first syllable of the word as a whole.