If not macrons, use ACUTE ACCENTS to indicate vowel length.
The modern acute accent evolved from the Latin apex which was used to indicate vowel length.
I understand macrons are hard to type and perhaps that’s why they’ve been excluded from this course, but acute accents are used throughout Duo and are far more accessible than macrons: á é í ó ú ý
Regardless of whether you go with macrons or acute accents, I think it’s important to indicate vowel length when introducing new vocab to the learner, as it’s phonemically distinctive in Latin. The video below makes the case very well.
Did the ancient Romans use macrons and/or accents to indicate vowel length? Or are you suggesting that it's an essential addition in order to be able to learn Latin properly?
I'm asking because when I first learned Latin, many years ago, it wasn't something I ever saw. So it seems odd to me. But so many people have asked for it or expressed dissatisfaction that it's not included, that I'd really like to know why they consider it so important.
Yes, they did. Watch the video and check out the Wiki article I linked in the OP. The ancient Romans were careful to indicate vowel length in their inscriptions, and if you don’t get the vowel length right, you’ll confuse the word for anus with the one for old woman!
The reason why you probably weren’t taught it is because these diacritics were carved much lighter than the letters themselves, and have worn away over time making them easy to overlook if you’re not paying attention. The Wiki article goes into this.
There’s been a revival in modern Latin with a push towards making macrons (or acutes) standard to avoid ambiguity in the pronunciation of minimal pairs. (e.g., annus, ánus, anus)
This is not possible in the current tree for technical reasons. The contributors may be considering changing how this is handled in a future tree version, I don't know. If so, and they do change, be aware that it will make the next tree version take far longer to develop, and when the new version is rolled out it will show skills as having a lot of new things to learn (possibly uncomplete them all) even if they were just old words with the macrons/accents added.