Dear fellow ESL speakers, be honest: how often do you find yourselves saying "yes" in your native language when speaking English to English native speakers?
Yes, the question is born out of my frustration at all the Heated Rivalry fanfictions that have Ilya saying "da" far too often and in absolutely normal situations. Sorry, but that's not how reverting to your native language works, actually.
I have been known to use my native language in the following situations (but it's Linguistics, really):
spotting a horrifying pest I am mortally afraid of: screams in native language
getting hurt: the equivalent of "ouch" in my mother tongue (sorry but when in pain I can't be expected to translate my instinctive reaction).
counting: if I count in English I focus on the words not the numbers, so it's a pointless exercise.
frustration: you know when you're trying to do something, but for some reason you're not having any success? (looking at you, demonic jar I can't open) That's when the native language comes out. It will be either a persuasive "come on!" or an angry "why won't you open you evil jar" depending on the number of attempts. It will be, invariably, in my native language.
tiredness: I barely remember my own native language when I'm tired. I'll try my best in English but be ready for grammar to go out the window and for a few choice words in my mother tongue, mostly mumbled beyond comprehension.
For balance, I should also add some other situations when I totally use my native language on purpose because of semantics, thus I whole-heartedly approve those usages in fanfiction (but it's still Linguistics, really):
terms of endearment: yes, darling and sweatheart and honey and what-not are fine. However, I will call my loved ones by names my heart resonates with on a deeper level, and that's going to be in my native language.
saying "I love you": now, the English language is awful for expressing love because you people only have ONE VERB, whereas there are MANY different kinds of love. So I will say "I love you " in my mother tongue, it's just better that way, trust me.
idioms that I love so I will teach to my foreign loved ones, with the only purpose of using them in conversation. And also because everyone needs enrichment.
insults: if you've just tried to run me over with your car while I was crossing the street with the PEDESTRIAN GREEN LIGHT ON, you bet I'll have words while you speed away. And those words will be in my native language (let's file this under fear and/or anger).
Wow, this turned out a lot longer than I thought. Sorry not sorry. Do tell me when you use your native language mixed with a foreign one! (And please don't tell me you use it to say "yes" :D)