Mis,
The LV versus RU language question is a sensitive one. There is still some cultural tension about the topic.
I learn LV as the family here speaks Latvian, but there are very few LV speakers who don't also speak RU. In Riga it is rare to have someone who doesn't speak LV.
In Riga, about 1/4 of the population speak enough English to converse, some speak better English than I do.
Food took some time to get used, but not much. Now I can understand most of the labels, and when not, I just use Google Translate. A lot of the products on the shelf these days are imported, so the packaging isn't as usefull as the shelf listing, which is almost always in LV.
The Latvian language itself is fantastic, but hard to learn coming from English/Latin. It is in itself, relatively unique, with historic roots.
The Russian/Greek (Cyrillic) alphabet is also unique. If you can read latin languages, then RU is just confusing to sound out (similar letters have different sounds.) It is best to at least learn the simple greetings in RU, in order to respond in public (to old ladies on the bus.)