Audio courses vary considerably in how (or whether) they review what they’ve already taught. I group them into three general categories based on how useful I’ve found their review methods. I find a certain method of review a great foundation for conversation.
The most useful: Review by creating new sentences
Some courses teach new material by asking users to create sentences in their target language by translating sentences from English. For example, such a course might teach that hablo means “I speak” in Spanish and español means “Spanish” (the language). “How do you say, ‘I speak Spanish?’” I pause the audio and answer, “Hablo español.” The teacher or better yet a native speaker says the correct sentence, and I repeat.
The course goes on to teach other material and then comes back and reviews the word hablo by asking me to make a new sentence. “Francés means the French language. How do you say, ‘I speak French’?” Answer: Hablo francés. Now I’ve reviewed the word hablo and created a new (for me) sentence in Spanish. After an hour, I’ve said a lot of new sentences aloud, and after 10-12 hours, I find myself starting to talk to myself spontaneously in my target language. That’s a tremendous foundation for conversation.
Courses in this category include Michel Thomas, Language Transfer, and Boostcamp (by Language Transfer)–the same courses I mentioned in my recent blog article, “Creating new sentences aloud, part one.” https://oregonpolyglot.com/2018/11/12/creating-new-sentences-aloud-part-one/
Audiolingual Method courses (such as the old FSI courses available for free on the Yojik website) fall under this category as well. Learners are encouraged to memorize the dialogs at the beginning of each lesson. Then, in the grammar drills section, certain sentences from the dialog are used as model sentences for the drills. Following cues, learners create new sentences by substituting words or somehow altering the model sentences (e.g. making them negative, changing them into questions, etc.). They then hear and repeat the correct answers. They’re supposed to do the drills with the book closed. It’s possible, however, to listen to and/or read the drills with the correct answers once or twice first, then do the drills one or more times with the book closed. No matter how it’s done, they review by generating new sentences in their target language or learning 6-12 sentences that exemplify a grammatical point instead of just 1-2 sentences.
Many people claim that Paul Noble is similar to Michel Thomas, but when it comes to review, it’s not.
Somewhat useful: Review by recalling already-learned sentences
Audio courses in this category start off the same way–teaching one or two sentences that exemplify a grammatical point or a useful expression–but review by asking users to recall the sentences they learned earlier. For example, the word hablo is taught with the sentence “Hablo español” and reviewed with the same sentence, “Hablo español.” After an hour, I’ve said “Hablo español” several (or many) times. After 10-12 hours, I’ve learned a fair amount of useful example sentences, but I don’t spontaneously start talking to myself in my target language. (Other people have reported that they do, but that hasn’t been my experience personally.)
There’s a way I get around this shortcoming: After a lesson, I review some of the sentences on my own, and then create new sentences by substituting words from one sentence into another (and hope that I don’t make grammatical errors in the process, since I have no one to check my work). I talked about this in my blog article, “Creating new sentences aloud, part two.” https://oregonpolyglot.com/2019/01/25/creating-new-sentences-aloud-part-two/
Courses in this category include Pimsleur, Paul Noble, Rocket Languages, and Glossika. They’re all fine courses. I use them and recommend them to others; I just have to work harder to supplement them in order to get the same results as the courses in the first category.
Less useful: No review
Next you have many courses that include no review whatsoever, but they at least provide a lot of example sentences. I have to split my time between continuing with new lessons and reviewing old lessons. (Granted, even in the first category, I might study a lesson twice, if the material is completely new and difficult for me–but twice is sufficient.) Here, spaced repetition might be useful. Hypothetically, I could review a lesson after a day, a few days, a week, etc. In addition to review, it’s also helpful for me to create new sentences on my own after reviewing the lesson, though I have no way to verify whether I create the new sentences correctly.
Courses in this category are basically audio phrase books, like the old cassette Language/30 courses (some available now for download at eStories). A good contemporary example is Book2 (also called 50 Languages), which is free of charge. I like these courses, too, but they aren’t my first choice.
Some audio courses are primarily lists of words to be repeated. They’re still far better than learning just from a book without audio, but pedagogically they’re far inferior to everything I talked about above. Review means replaying the audio many times, and if I make my own sentences, they’ll probably be both grammatically incorrect and unnatural to native speakers’ ears. I would consider these courses last resorts or mere supplements.
Examples include the Behind the Wheel series and Vocabulearn. Actually, a surprising number of courses aimed at tourists and inexperienced language learners fall under this category. I tend to lose interest after 10 minutes and am not motivated to review them, personally.
No matter what
My approach as a beginner is to create new sentences and to use mostly audio courses whenever possible. A textbook with a lot of audio (e.g. Dos Mundos) or dialogs with transcripts (Olly Richards’ Conversations series or Innovative Language podcasts) are helpful for reading and listening practice and can grow my vocabulary, but I tend to minimize written material as a beginner if I can. While dabbling in Tagalog this winter, I didn’t have that luxury, but in Swahili, I do.