So recently I've met a Japanese person whilst playing League and we started to talk a bit over the group voice chat. Although my Japanese is still at a very basic level we understood each other pretty well. Anyway, because I was talking to a friend on Discord at the same time in another language he was understandably confused, so I tried to clear things up by saying "日本語を話してないときはDiscordでともだちと話している" (Whenever I'm not talking Japanese, I'm speaking to a friend on Discord). He seemed to understand what I meant to say so I left it at that. A few days later though I finally started learning about "たら", "なら" and "ば", and I remembered my conversation with the Japanese guy. Would using "たら" instead of "とき" have been the better choice?.