Transitive/Intransitive verbs are an important part of Japanese, but this distinction is not something that most native English speakers are even aware of. We have a few exclusively transitive/intransitive verb pairs, but they’re few and far between. Even so, we know it sounds weird if I say, “He falled the ball.” That’s because “fall” is intransitive, and the phrase should use the transitive verb, “drop.”
It’s true that there are some patterns, for example a verb that belongs to a transitive/intransitive pair and ends with a 「す」 suffix will be the transitive variant. If that doesn’t apply, it’s usually safe to assume that a verb with an 「*える」 suffix is transitive, e.g. between 上げる and 上がる, the former is transitive.
But I think we can do better.
This userscript wouldn’t be particularly useful to anyone who only wants to read or listen. But, anyone aiming to speak and write will have to know the difference intuitively to do so properly. So here’s my idea:
For all non-する verbs, make the correct answer cause a “wobble” and a retry the exact same way WK does when you give it a valid Kanji reading it’s not looking for. Instead, all answers for transitive verbs must include「を」and all answers for intransitive verbs must include either 「は」 or 「が」 to be counted correct. Ex:
を交ぜる (To mix; transitive)
は交わる or が交わる (To intersect; intransitive)
が交じる or は交じる (To be mixed; intransitive)
As of now, I can correctly discern whether most verbs I’ve learned are transitive or intransitive, but I usually have to stop and think about it. If I drilled the vocab with a script like this, I’m hoping the difference would become ingrained to the point that を交わる would instantaneously sound wrong and bizarre. That’s the kind of understanding I’d like to achieve.
I think this would be especially beneficial to speaking, given that any slight pause to consider grammar is always acutely obvious.