I consider myself really lucky that my parents spoke to me in different languages. Quite a few of my cousins regret only learning how to speak English. I can still speak 2 of the languages they taught me but I've almost completely forgotten Italian. Like the author, I guess my parents didn't really see the need to speak it when they moved to Canada but I can kind of understand it still.
I love going to konbini whenever I'm in Japan but do yourself a favour and don't go to one for every meal. If you want a bento or some small dishes, there are lots of good and affordable ones at the grocery stores and department stores. They even discount them by quite a lot near closing time. Check the basement or top floors of the major train stations as well.
There's lots of good restaurants as well all over the place and even at the top floor of many Yodabashi (a giant electronics chain). Don't be afraid of places that don't have any English signage, you can usually request an English menu or see if they can just recommend you a good dish if you're adventurous.
If you're hopping onboard the Shinkansen (bullet train), grab yourself an ekiben at the station before you go, lots of delicious regional dishes to try out!