Spanish speaker here… and I’ve been using mostly the english meaning provided, but when faced with some unknown english word I’ll switch it for some more common version, as recalling both the japanese word and a new english word seems unnecessary .
last time was “Boisterous”… changed to clamor or noise seemed like the right thing to do 
At some point I actually thought about putting in translations as synonyms, but it turned out to be too much of a hassle. As most of the available sources are in English, there would be no end.
And sometimes, even looking up an English word doesn‘t help much, like for discerning…
Je kan je eigen synoniemen toevoegen terwijl je reviews aan het doen bent. Dus in feite kan je via WaniKani ook JP-NL leren. 
Maar dan moet je even de tijd nemen om alles in te vullen.
Ik ben tweetalig opgevoed, dus ik doe dat zelf nooit, maar de notities die ik soms toevoeg voor de mnemonics zijn af en toe een mengsel van Engels en Nederlands.
I normally stick to english except if some mnemonic on my mother tongues appears on my mind that really sticks.
Hello! Fellow ESL here.
I just do it all in English. But my English is pretty damn advanced by now to the point I’m basically native.
That said, I still find new English word thanks to WaniKani. Like geoduck. Or cleat.
Thanks all, this is very useful. I’m not too concerned with single words but more with (eventually) making up whole/complicated sentences and the speed I’ll be able to do that with from Dutch to English to Japanese 
. Thanks for sharing your experiences!
Hi! Indonesian here. Just my two cents as an addition to what @Omun had said (I used Google Translate to find out what he had said btw). I stick to English, so I’ve never added my language as synonim as an alternative answer so far, but I have many notes in my language(s). If things got hard on me, I even use my language to explain Crabigator’s default explanation and also Vocab’s example(s). I create my own mnemonics (in any language I know) to help me remember some meanings & readings. If I’m really stuck after I search online and I’m still confused, I can always ask on this forum (usually this thread), as far as I know many people here are nice and helpful.
Native Finnish speaker here - I do it mostly in English, but when there are words I haven’t really heard before or feel like I won’t remember in English, I add a synonym in Finnish Sometimes I may also add a simpler version of the same word in English and add extra explanations / mnemonics in any language I know (Finnish, English, Spanish, French).
I’m a native German speaker but I’m also one of those people that is more comfortable with English so I’m fine with sticking to that.
Sometimes I still get tripped over. I recently looked up 軒下 which Jisho lists as “under the eaves” and then got out my English-German dictionary for “eaves”…
I actually thought geoduck was a pokemon. Then I looked it up and it turns it’s just as creepy as a pokemon in real life would be.
Yuk… I just checked it out… people eat that?? 
I mean… it looks like… Hmmm…
People generally eat almost everything 
Wanikani is an excellent way of learning English words.
Yep, for non-native english speakers Wanikani ends up helping to learn two languages at once.
As a Dutchie myself, I’d say stick with English, you might learn some new vocabulary along the way (win/win imo!)
i’ll only add synonyms in german, when i feel there is some meaning lost in the ja-en translation where it is (more) preserved in ja-de.
German native here. I never really thought about the german equivalents during my learn sessions. However, what I sometimes find useful is creating my own pronunciation mnemonics if something sounds just like a german word (or similiar at least). For example: north = kita = another word for “Kindergarten” in german. I find it easier to memorize that than the wanikani mnemonic. Other than that you might learn some new english vocabulary which is also nice!
hello! i tend to use the english words to remember what’s going on, sometimes adding my own in english or native (like population i describe myself with biiiig mouth full of people haha). i remember english words first usually.
i think whatever helps is useful, so i don’t think the language matters as long it’s sticking to your mind (try to build own mnemonics if wanikani’s aren’t sticking to your memory)!
ofc this website asks for english translations, so you probably can’t get around that issue. but i think it’s naturally and good to also think about the kanji in your mother language to remember the meaning. i hope you won’t get too discouraged!
i don’t get the connection between north and kindergarten ^^ even the reading of north is kita. the german meaning of “kita” has no logical connection to the japanese 北。
Kita is short for Kindertagesstätte, no? Sure, 北 is pronounced differently but it still sounds somewhat similiar.
Hiya, another German native speaker here. I’ve made it a habit to add the German equivalents to every Kanji and vocab item during my lessons. Sometimes I’ll think of the English version first during reviews, sometimes of the other, so I can type in whatever comes to mind first.
I use this userscript to add synonyms during lessons.