I am in a similar situation with German as well. At times, it's been frustrating because I feel like I should know things that I've forgotten and I want my German skills to come back to me more quickly than they are. Yadda yadda yadda. Managing that frustration has been a big part of reviving my German.
I think the most crucial thing in a situation like this is to identify your weaknesses, especially if you feel that producing your target language is difficult. In most case, that difficulty is rooted in a feedback loop we get into when we are aware of our weaknesses to some degree and it makes us overthink things and it just tanks our confidence. So the key is to shore up your weaknesses.
For me, I lost a significant amount of more advanced vocabulary even though I have retained a lot of kind of vocabulary anyone learns with German up to B1 level--common words and high frequency words., that sort of stuff.
The other weakness I have is with grammar, in particular with recalling a lot of the more precise and nuanced grammar that has become fuzzy and vague, like case endings, more complex sentence structures and certain fussy prepositions--the kind of stuff that wasn't a lot of fun to learn the first time around and even less fun trying to review them after a decade of not using German.
Anyhow, knowing what my weaknesses were let me focus on what resources that would be most worth my time. In my case, I decided on:
- Reading at as an advanced level as I was comfortable with, to expose myself to grammar and vocabulary I had forgotten. For me, that was texts aimed at advanced learners or more general stuff like fiction for native speakers that isn't super difficult. With a language you have known at an advanced level in past, you want to aim for a reasonable degree of reading comprehension. I'm a believer in extensive reading, but not for this. You need to be able to understand what you are reading so your brain can start putting those stray pieces of memory back into place. If you need to look up some words or phrases, that's fine, even native speakers have to do that sometimes, but if it's completely going over your head, do not feel bad about finding more accessible reading to help build your skills back up. Start at a level that you can build up from.
- Vocabulary training to rebuild vocabulary. In my case I'm using Memrise, as they have a lot of German courses (Spanish too) for all levels, but there are plenty of options for this, like Anki, Quizlet or offline methods like flash cards or writing out wordlists. But you gotta do this--there is simply no substitute for having a solid vocabulary. Even if you feel confident with more common vocabulary, start learning some new words and expand your vocabulary. You can never know too many words.
- Grammar workbooks and oral drills. In my case I didn't need to get anything new as I have a ton of this stuff from years backs. Oral drills especially are very helpful for rebuilding confidence with speaking your TL. In my case, I do conjugation drills where I recite verb conjugation out loud, as well as shadowing 50languages audio files from their Phrasebook.
- Dictation with audio of well-written texts that have a precise transcription. I learned German in school and we did dictation the old fashion way with the teacher reading a text slowly, including saying the punctuation out loud in German, and we were graded on every detail. Unfortunately, it can be really hard to find resources to replicate that without a paid teacher, but I'm making do with the listening portions of past papers for German certification testing--there are various places online to get these sorts of things for free, for several different languages, but at the moment I'm using the ones you can get at SQA.
- Easy German on You Tube. Their videos are really good for advancing learners because expose you to a wide variety of topics and vocabulary without it being too tedious. They also make Easy Spanish videos too, and I suspect that those are largely the same sort of format as the Easy German one. I haven't seen too many of the Spanish ones to have an opinion.
If I could afford the kind of tutor that could help me at my level and who was good enough of a tutor to respect my needs, I probably would get one. But since I can't, I don't use a tutor. If that's an affordable option for you, great, it can help a lot with keeping you motivated. But if you can't find a tutor that suits you, it's OK. The truth about language learning is it's all about the work
you put into. Tutors are mainly good for answering your questions, giving you feedback and keeping you on track (and I used be an English writing skills tutor, so I know
) and you can largely find what you need in those areas through language learning communities like this one and a bit of self-discipline and determination.
Lastly, I think it's really important to make the learning process enjoyable and not excessively tedious, so I also do other things like watching German films and TV and follow for German Twitter accounts to just keep my motivation with German going and have fun, because it can be a bit of a slog to work my wonky, sad German. But again, once you identify your own weakness, tailor your study regime around that. Good luck!