The reasonable first reaction to songs as a teaching method is scepticism. It sounds like something for children, or a novelty that will wear off in a fortnight.
Worth addressing directly, because the objection is sensible and the answer is fairly mundane.
What Singing Actually Is, Mechanically
Strip the associations away and singing along to a phrase is: producing the phrase out loud, at a fixed tempo, with correct intonation, repeatedly.
That's a description of speech production practice. It's what a tutor would have you do, what a drill would have you do, and what every serious method agrees is necessary. The music isn't replacing the practice — it's the delivery format for it.
So the question isn't whether singing is a legitimate way to practise. Obviously it is. The question is whether it has a disadvantage against the alternatives, and there isn't an obvious one.
Why It's Associated With Children
Because it works extremely well on children, and because most existing musical material was made for them. Alphabet songs, counting songs, nursery material.
That's a fact about who the market has been, not about who the mechanism works on. The underlying processes — memory for melody, reward from music, motor rehearsal — aren't developmental. They don't switch off at eighteen. Adults respond to music at least as strongly, and arguably more.
The Advantages Are Practical, Not Magical
Nothing mystical is being claimed. The benefits are ordinary and countable.
You'll do more repetitions, because you'll tolerate the repetition. The tempo is fixed at conversational speed, so you can't practise too slowly. The melody carries intonation, which is otherwise close to impossible to teach. And the material tends to stay with you afterwards, extending the practice at no cost.
Four practical advantages. No claim beyond that.
What It Isn't
It isn't a replacement for using the language with people. It isn't a way to skip the work — it's a way to make the work bearable enough to accumulate.
And it isn't a shortcut. The same repetition is required. It's just repetition you'll actually do.
About Outputly
Outputly uses songs written for adults, teaching the phrases adults need, at conversational tempo. The format is unusual. What it's doing underneath is completely ordinary speech practice.