The answer to this, annoyingly, is - it depends! How long it takes to learn a new language can depend on so many factors, such as your learning style, how much time you spend learning each day, how much practice you put in, and even the language itself.
As well as this, some people just take longer (or are faster) to learn than others.
Babbel professionals agree with this, but they do claim that it can take just 3 weeks to be able to have a very basic conversation in your new language.
This does not come easily though, as you will need to be putting in the work for it every day and practicing it often.
Different languages take different amounts of time to learn, so research how long you can expect your chosen language to take and aim for that.