So, I see tips on various apps around here, I rarely get curious enough to try anymore (I know what works for me, and most simply don't even look tempting). But this one seemed interesting, so I gave it a try and would like to make a proper review. With pros and cons, and who this might be good for, and for whom it is a waste of phone memory. I tried it out on Hebrew, a language I want to learn, and German (I am A2ish), while learning from Czech (my native language with few digital tools), and English (so that I can quote it better). I approached it with open mind and a bit of hope.

Short version: a possibly ok supplemental exercise for either beginners in unpopular languages, or beginner learners who are natives of unpopular languages, and struggle to find a digital tool based in a language they are comfortable with. But other than that, no, not worth it.

Full version:

1.The amount of languages and their combinations is one of the huge advantages of this product, it targets the otherwise not well served learners. Of course this would be the easiest achieved with machine translation, but BB claims everything is human made. But there are still issues as if it was machine translation, such as the homonymes. For example the Czech translation of the word "hug" is "objetí". "Obětí" is pronounced the same, but means "victim".

=a good thing, but have a look at Clozemaster anyways

2.The promises are rather wild and unrealistic. 2000 words are nice for a beginner (and especially for one learning a language with scarce resources), but far from sufficient, if you want to get further than that. So no, BB is not "the last app you need". And no, the "advanced" level in the app is not advanced at all. 2000 words are solid for A2, perhaps B1 (but many courses teach more). Also, this is very far from a full course, which I'll mention later.

=perhaps opt for Speakly, Clozemaster, or MemriseDecks

3.The main part are audios.

3A.This is not that great in my opinion, because Blue Bird has no web based version to use at home, comfortably on a computer When I want to use an app, I am usually in a situation requiring silence. So, the whole idea of repeating after an audio is a bit hard to combine with only app being offered. If there was a website, I'd find it good (Language Transfer is audio+speaking, and it has both a website and an app).

=a matter of personal taste, you might like this

3B.There is too much wasted time on the base language in the audios. A large part of each audio file is wasted on things like "Welcome to Bluebird Languages. In this lesson, we'll focus on learning..." and "First, just listen to how it's pronounced". This could be nice for your first audio lesson, but not in every single one. And this is a large part of each audio file.

=most coursebooks' cds are wasting much less time

3C.The quality of the audio is good, and I can believe it is really fully human made.

=so yes, if you struggle to find a collection of audio vocab flashcards in your target language, it might be good for you

3D.The teaching part of the audio (so, outside of the loooong comments in your native language) is based only on repeating words, or phrases. There is no dialogue, no richer listening, no need to come up with an answer. This is a bit sad at the "higher" levels. There are supposed to be dialogues in the "Conversation" section, but they are locked, and I honestly don't think the lessons will be that different from all the other sections. If anyone has paid and tried, please correct me. And the promise "77 twenty-line dialogues between a woman and a man bring all the learning together in increasingly complex linguistic situations." makes me worried, because the jump between repeating words and understanding long dialogues looks huge.

=Language Transfer, or the audio coming with Assimil or most coursebooks is likely to serve better. Or Glossika is based on repeating after audio and known to be very good for some types of learners!

4A.The exercises are underwhelming. BB promises: "Premium quizzes, photos, bilingual subtitles, flashcards and pronunciation analysis included in every lesson". Hmm, the quizzes are mostly just tapping on a word, sometimes putting together a word. Or there was something like the "wordbox" exercise we know from Duolingo. Perhaps there are some premium features for paying users, but it is weird that BB doesn't show their existence anywhere, except for the option "personnalised courses" (thematic ones). So, I somewhat doubt they exist.

=just a worse version of Lingodeer,Duolingo,or Rosetta Stone

4B.SRS was promissed. Where is it? There are quizzes, but no sign of SRS. Not even "unlock SRS here by paying". Oh, I see!!! From the FAQ: "Bluebird uses the scientifically proven spaced repetition learning method to optimize both language acquisition and language retention. Just listen and repeat, it’s that easy!" :-D :-D :-D They don't know what SRS is!!!! They think it is a space in the recording, in which you repeat a word :-D

=any SRS app will do

5.The course organisation and "methodology": Weird. There is no real method.

5A. BB is proud of not teaching anything systematically. Even in the verb section, you just dumbly repeat, no rule that could make it easier is explained to you. Ah, again from their FAQ:"Bluebird teaches grammar implicitly, through examples that illustrate patterns. It does not teach grammar explicitly (e.g. “a prepositional phrase is a modifying phrase consisting of a preposition and its object.”)." No, this is again a misunderstanding. For implicit learning, you need much more content, and even then it is very hard for many beginners. But "explicit" teaching doesn't mean flooding the learner with terminology. They are hitting a straw man here and trying to get customers by scaring them of grammar.

5B.There is no order in the lessons. That would be fine, if BB was presented as a supplemental vocab app. But from something trying to be more, I'd expect some guide on the order of lessons, or real instruction. You get the basic vocabulary (70 hours of audio promissed, but a large part of the audio is wasted on the useless comments I've already mentioned, and on gaps for your answers), then the verbs (no explanation, just repeat), "Creating sentences" (which is still the same, no guidance on actually creating sentences, you just repeat a few examples), "powerfull phrases" (the same thing), and than the locked "conversation.

=any coursebook will serve better

5B.No reading instruction. "Bluebird’s main focus is on teaching you how to speak a language and to understand the language when spoken. If your goal is to learn how to write in the language of your choice, Bluebird will help you to learn phonemes and sentence structure, but it is not our main focus." This would be legit, if at least the written words were a bit bigger and easier to see. But no, they are not teaching sentence structure, and you need to guess the phonemes' correspondance to the script (fortunately, I had learnt a bit of alefbet before).

=if you're not interested in reading, then I wish you a Language Tranfer course in your language, it will do a good job. Or perhaps Pimsleur or Michel Thomas. Other than that, I think most learners definitely need at least basics of reading.

6.The visual design is very bad and counterproductive. The app is made to be nice. Understandable. But at the expense of functionality. There are huge photos, that make the quizzes hypereasy (it also goes against what I've just quoted. BB is not teaching you to understand the language as it is spoken, at least unless random natives carry around photos of everything they say :D ). The written words and phrases are extremely tiny, even I find reading them tiring, no idea how would most older learners do. And in the exercises, there is no button for repeating an audio, for example. Really, the design is meant to impress, not serve.

I hope this helps someone considering what to use. I've just wasted my time, so that you don't have to :-D But I admit there could still be some value, for people in need of tools in an unusual language combination.