ABA English offers a natural way of learning English through watching films related to real life. One of my former adult students from Italy remarked that this site was enjoyable and that it made learning English seem like less work than learning in the classroom. ABA English offers a trial period so that anyone can try out the program and benefit from their videos for free. If learners prefer to advance in the program, they can sign up for the Premium services. Otherwise, learners might prefer watching You Tube for free videos about the English language and singing along with some You Tube Music videos with the lyrics printed for singers. Singing enables learners to practice the flow of sounds in a natural way.
For unfamiliar words, I would turn to the Merriam-Webster Dictionary online, to the Oxford Dictionary online, or to a general "word-of-the-day" e-mail list for which one can sign up to get daily messages with new vocabulary. Not even a native speaker will likely know all of the words that one receives in the e-mails of words each day. Students should pay close attention to the etymologies of words. An etymology is an explanation of where a word came from and possibly how it changed in both form and sound over a long period of time. The study of the origins of words makes a challenging language like English all the more fun because it links the language to historical origins and to various cultures.
The best online English language lessons will include some additional learning materials. That means that apart from the classes, there will also be some vocabulary sheets, a grammar bank, relevant exercises, and tools for self-evaluation. These things are definitely important to look for. It makes it much easier to learn a language when you have access to the proper tools. No matter what it is that motivates you or the person you know to learn English, there is an option out there for you. Research the various courses available and see what is best for you.