#but i want to eait until i've developed conversational proficiency in a non-indo-european language

[faitsansorganes]

Btw the efficiency with which you learn a language really depends so much on the methods you use. While learning by translation (e.g. that jabłko = apple) works to some degree, any speech or writing in your target language will have to travel through an additional mental layer before you can understand or say it—as opposed to if you learned the words more directly (e.g. that jabłko = 🍎). Moreover, the applicability of translation as a means of approaching your target language falls apart as the linguistic distance between your native and target languages increases. Going from one indo-european language to another, you'll be mostly okay as long as you remember some language-specific rules, but outside of that things become ever more difficult. Much of Japanese, for example, cannot directly translate to English. There is absolutely no English equivalent for the nuances in choice of first- and second- person pronouns (or the choice not to use a pronoun at all!) in Japanese that can at all be understood when translated as the all-covering "I" or "you". Attempting to understand such linguistic differences in the terms of English does a disservice to one's learning and does not respect the Japanese language as something which exists on its own right, independent of the English language.

Now, to a certain point, using your native language to learn a target language is necessary. For the time being, the simplest resource for learning basic and topic-relevant words is a vocabulary list or an inter-language dictionary. Any introductory grammar is also much easier to learn the rules of in one's own native tongue. While one most likely could learn a language solely through engaging in media in that language, much as a baby learns their first language, without any guidance (which as yet seems only to be provided in full-time immersion programs designed for this purpose, which require not only a significant amount of money but also the free time not to be working at all during the duration of the program) this will take years.

That being said, having initially learned something in one's own native language does not mean that one should practice it in said native language. If you are using flash cards, then, using the aforementioned example of "jabłko", it would be better to have the definition side be a picture of an apple rather than the word "apple". To practice the conjugation of the relevant verb "jeść" as well, it would be better to have a card which is something like "ona [jeść] jabłko" than to have a card which requires you to translate "she eats an apple". (Obviously after a certain point, one will have to develop a method of telling oneself which tense is needed, but that is its own subject.) Through this, one develops a more direct and "intuitive" sense of the target language.

Learning in such a manner presents more initial difficulty, as it requires much more individual effort than does simply memorizing ready-made lists of words and grammatical rules, but the efficiency gained in learning and the depth gained in understanding more than makes up for this.