Hi Sara, it is a very interesting topic. As far as I am concerned, I prefer to learn languages online.
I can compare two different experiences.
On the one hand, I started learning English at school like most people. Each year, we had a different teacher, I always had a feeling of discontinuity and mess. At the end, I had got different knowledges but they were not organised and I was barely able to have a conversation or to read a short story.
It was very hard to get over that.
On the other hand, I started learning Chinese both in class and online. As some people know, Chinese tones are very important and not so easy. At school, you don't decide the pace of learning, the teacher cannot care about everyone's tones.
Online, the teacher only cares about me. I learn faster than at school, if I have a problem we can work on it as long as necessary. Besides, I will be able to keep that teacher throughout my learning and she will always be aware of my strengths and weaknesses. I think that is very valuable.
Both have their good and bad sides.
I like the social aspect of group lessons. I like meeting other learners and sharing the learning experience with others. PaulBeacon mentioned stress levels. For me the stress level is much lower in the classroom, because I'm not in the spotlight, it's not all about me. Of course, it all depends on personality, but I sometimes get nervous when too much attention is on me. It is cheaper to get a professional, native, experienced, well prepared teacher, when taking group lessons. For the language I am learning, such teachers are quite expensive for one on one lessons, even online.
The advantages of online lessons are obvious. I can choose the time and the teacher, take lessons in a language that is not offered in my town, quit when I want, change teachers as I like, no travel time, no missed lessons when I can't attend. The lessons are tailored to my needs and I can choose what I want to do. This last point however is both good and bad, as I usually don't know what I want to do and it sometimes becomes a problem.
Which one I would choose, I really have to decide on case by case basis. For example, now I'm taking Italian lessons in the classroom and German lessons on italki.
For me, there is no right or wrong answer here. It depends on the student and, indeed, the teacher.
In the classroom you have physical presence. You have the ritual of going to class. And, you have other students in class. When I worked at a school in France, we made big efforts to make coming to school not just about having your class but also about a learning experience. I think this can be a big deal for some people. Obviously, the downside is that you have to book a time and be organised towards that by travelling.
On Italki (Or other online platforms) you some of the social aspect of learning. It is less experiential in some ways. But, you also have a degree of privacy. So, for nervous students, I think it is better. They are in a one-on-one environment and in the comfort of their own home. This can reduce stress level significantly. Also, for all students, there is the convenience factor. It is much easier just to log on to Skype than it is to get in the car or get on public transport to travel to a school.
For the teacher, it is also different ball games. Online you do not have to travel and usually have one-on-one classes. I find it makes it easier to develop better relationships with students. Also, it takes transport out of the equation. On the downside, i miss having a classroom and whiteboard ... and marker pens.
