At LingQ, each of our lessons consists of audio and text, which are available for download. These are mostly provided by our members. We are having a discussion at our Forum on what constitutes the ideal length of content for learners at different stages of their learning.
Here is what I had to say in a recent comment on that thread.
Our content generation system is somewhat anarchic. We rely on what our providers feel like creating or contributing. This will vary. What users are looking for will also vary. Hopefully, over time, this spontaneous generation of content is working. I am amazed at the amount of content I am finding in our library for Czech and we have just started. I am also starting to import content from Radio Praha, and will soon add other sources.I suggested some length guidelines for different levels of content but we are happy for all content. There is no direct relationship between the effort required to generate content, and the value to learners, all of whom have different tastes. I have said that we need to improve the ability of our users to directly reward content producers whom the especially appreciate. We have this on our list, our long list of improvements. We used to sell content and few users bought content when free content was available.We are trying again with our store and we will see how things develop there. We are also looking at other things we can do. In my own view, in other words for me personally, what is most important in content are the following: These things are subjective and can vary with language and with my stage of learning. 1) Interest level, which is obviously personal and subjective.
2) Voice and sound quality, and clarity and general quality of narration.
3) Length, and I have indicated my personal preferences for length at different levels of difficulty. The speed and convenience of LingQing has improved to the point that I am quite content attacking difficult content at an early stage, as long as it is of interest to me, not too long (2-5 minutes long), and the voice is pleasing and clear. That kind of content is preferable to content of little interest, with poor sound, and either too short or too long. I can read it and listen to it over and over while reviewing the flash cards. I can also play the text to speech on the flash cards, and even record the text to speech from the flash cards on to a sound file for a sort of audio flash card review. I know that even if I do not fully understand while reading, and understand little while listening, this is only a temporary situation and in time the fog will lift. I have trouble going through mountains of uninteresting content, however easy. But that is only me, and other users have different tastes and strategies in learning. It is great if there are translations and notes for beginner lessons, and videos also add value. I generally go to google (Czech grammar etc.) for additional help on the language when I need it.