If someone wishes to learn from English with no previous success in language learning either French, Spanish, German or Italian then I recommend starting with Paul Noble’s audio only courses, published by Collins. For 8 further languages, namely Chinese, Japanese, Arabic, Greek, Russian, Polish, Dutch and Portuguese I recommend the Michel Thomas series to absolute beginners. After these courses, or from the start for languages not covered by those courses, I recommend Pimsleur courses. All these are audio only courses and are done with no teacher following the instructions outlined by the presenter.
Once this audio material has been front loaded, it is time, if the learner is still enthusiastic, to work through a written course. Most of these also have audio which should be used earlier in the process rather than later. Good courses include such series as Colloquial by Routledge, the Teach Yourself series (older courses tend to be better than new in that series) Living Languages and the Essential grammar series.
To learn the material in the written courses I recommend my own method called the Goldlist method which is free on the internet if you google for it. It helps to memorise written material to the long-term memory with the least possible total time of engagement per word or phrase. It is more effective than having a teacher who will try to activate sparse knowledge too soon.
You should aim to develop fluency in reading because the difference between fluent reading and fluent speaking is three days of immersion. Not a hundred lessons at 20 dollars a shot. Teachers are only really necessary for languages where you cannot tell the pronunciation from the writing or which have highly complex writing systems – and for tonal languages for those encountering this for the first time. A teacher is more likely to impede the adult learner in most Inter-European language learning.
One small word of warning to the absolute beginner – be ready for words and phrases in the language you know to be used completely differently in the other language. Just to give you an example, take the English “What’s happening now?” In French this would be “qu’est ce qu’il se passe maintenant?” Now this means exactly the same in terms of what the French would understand as the English phrase “What’s happening now?” but if you literally translate each of the elements in the French phrase, you get “What is this that he passes handholding?” If a French person tried to learn English using a verbatim approach as you can see he would not make himself understood, but equally anyone trying to put “What is happening now?” word for word into French will find that they come up with something equally nonsensical to the French, moreover the words you would need to do it do not even exist.
I met an Australian one time who said he was “orry” when I asked him how he was. I said “Orry? What’s that?”
“That’s French, mate”,
“You mean ‘horrible’?”
“No, mate, it’s French for “good”, I’m good, mate”
“How is “orry” French for “good”?”
“What? You’re a linguist and you don’t know the French for “goodbye” which is “orry-vwar”?”
I smiled at the wit and then it gradually dawned on me that the guy wasn’t joking. This is the biggest hurdle people have at the beginning, an expectation that the target language is going to work just like their own, you just slot other sounds in instead of the English ones. Sorry, but it doesn’t work that way.
If you can get your head around that, then you are ready to approach a foreign language.