I used to live in Tallinn as well (American expat) and echo basically everything rvnx says here. Some of the older people from the Russian community speak only Russian, but you're much more likely to encounter this in Narva (east) than in Tallinn. Estonians are also well aware that they are a tiny country with a difficult language so if you're not permanently settling, there is little expectation of learning more than a few words of Estonian. Super easy to navigate the bureaucracy (if you can even call it that), file taxes, etc.

One thing of note, with the caveat it's been a few years since I lived there (although I stay closely in touch with friends and visit often... actually I am typing this from my airbnb in Tallinn) -- you might get some looks if you're brown or black. From my experience this is mainly from older people and it's pretty benign, but it's not the most cosmopolitan place and most people of color you see are "students" for visa purposes who have been there for many years and work for gig startups delivering food or driving Bolt (Uber equivalent). I never felt unsafe or anything, but there were a few uncomfortable moments during my time there as a person of color.