The one-at-a-time UX is too slow I think. I'd rather see N words at a time and select the ones I don't know.<p>I'm also not sure how to use this tool in a learning workflow since you have to be able to copy and paste a bunch of text. I guess the use-case is when you're reading articles online on a desktop device, but as you read the article you can already pinpoint the words that you don't know, yet this tool makes you paste the text back into the tool and reconsume all the words again.<p>A better version of this tool might be a browser plugin that lets you click words as you read content online and add to a vocab list. This way as you practice reading social media or news in Spanish online, you can accumulate words and then do something with them. Maybe export Anki cards or whatever it was that you had planned.
One suggestion for reducing the burden on your users would be to start making predictions about what vocabulary your user already knows, just based on what's known about word frequency and a short quiz pulled from the text.<p>I copied in a long poem and it looked like I was going to be prompted about whether I knew 1500+ "words" (are you lemmatizing the input at all, BTW?). If your user knows the most common verbs, they probably already know the prepositions, pronouns, and other closed lexical classes of words (and vice versa). If your user is familiar with less common vocabulary (e.g. something at C1), raise the word frequency threshold for checking if the user is familiar with the word. If your user is less familiar with basic vocabulary, don't overwhelm them with moderate and advanced vocabulary.<p>That would make the prompting portion more interesting -- you select the most discriminating words to zero in on estimating the user's ability (this is really how adaptive testing works). You could gamify this too, by essentially establishing the user's "vocab ELO" rating based on word frequency.<p>Admittedly, maybe my suggestion misses the point of your app in case the objective was to be sure that you don't miss any new-to-you vocab in a text. On the other hand, if you could do something along the lines of my suggesting, you won't overwhelm beginners and you won't exasperate more advanced learners.
I created something similar to this a while ago, but perhaps significantly more niche.<p>I like reading classical Dari poetry, but I'm not a native speaker. Every now and then, I read a couplet which has a word that I don't know, or that the dictionaries available to me (either from Iran or Afghanistan) don't provide clear explanations for.<p>I indexed a whole bunch of works from classical poets from across Central Asia, South Asia and the Middle East and created <a href="https://baytyab.com/" rel="nofollow">https://baytyab.com/</a> which lets me put in one of those words that I've come across, and see other couplets that the word has been used in to help me get a better, contextual understanding of its meaning(s) and usage(s).
I thought that this would look for unique words rather than just cycle through all words. You should have a default ignore word list that includes things like el, en, de, etc etc.
Shameless plug, I'm currently making an app that does the same thing for German: <a href="https://vokabeln.io" rel="nofollow">https://vokabeln.io</a>, it does not work 100% correctly yet, because german has just an infinite amount of compound words, but if you are looking for an app that extracts words from a text and then makes you practice with spaced repetition, then it gets the job done.