No, not from the heat.
To expand a little on what's in the sidebar:
I grew up in New York, speaking English. My father was born in Hungary, and although I heard a lot of Hungarian growing up, I never really spoke it as a kid. I learned French starting in seventh grade, in public school, and by the time I started college spoke it well enough that I tested into a Francophone translation course. At the same time, I started speaking more Hungarian, and when I was 21 I went to Hungary for a year, where all the latent Hungarian kind of came out. By the end of the year, I was pretty close to fluent, although I still had trouble understanding specialized spoken Hungarian (for example, political news on TV and that kind of thing). I also took German that year. When I went back to America, age 22, I started taking an intensive Russian course, which I continued for two years; then I spent a summer in Russia, and did another two years of Russian after that, although much less intensive. I also started taking Hebrew, at the local Reform temple. After the summer in Russia, I was in England for a year (studying Russian) and also took a semester of Mandarin Chinese. When I got back to America after that year, I took an intensive Hebrew course for a semester; three years after that, I took a much less intense Hebrew course for close to a year, dropping out at Pesach right before Barak was born. My Hebrew a year ago was not great, but thanks to Asnat it's come a long way since last summer.
Oh, and I've also taken American Sign Language, the full set of ten courses offered by the New York Society for the Deaf. I've done some interpreting, but I don't have a license.
The functional result of all of this is close-to-fluent Hungarian, latently very good but currently quite rusty ASL, Russian and French, no Chinese to speak of, survival German, and, B"H, rapidly improving Hebrew.
When I am in Vienna, I can get around fine with my German. When I'm in Hungary, my Hungarian is totally fine. If I am around French or Russian people, my French or Russian picks up pretty quickly, and right now my Hebrew is as good as it's ever been. What I can't do, unfortunately, is switch from one to the other. And that is a problem, because we are in Israel. Specifically, we are in Ramat Beit Shemesh. So this morning, I spoke English to my husband and kids, Hebrew to Barak's madricha, Hungarian to my granny on the phone, and then had quite a long conversation in French (she thought I was Belgian!!) with the French lady at the pharmacy. Then I walked outside, and someone asked me, in Hebrew, where a particular beit knesset was.
I told her. In French.
If someone comes up to me today and tries to speak Russian with me, I think my brain will melt and drip out my ears.