I think providing your student value for their money is important. The best way to do that is to find out what they want to work on in the target language and why, and build your lesson out from that point. What a student expects in a language exchange and what they expect out of a $30/hr lesson is rightfully different.

In a non-structured situation where I would not be charging or would be charging very little, we just talk about anything the student wants and answer questions and build vocabulary naturally. It is something I do with close friends and with intermediate students with a good base level who are practicing for fluency, but are not high enough to need specific language such like medical English, business English etc. I typically charge a student between 5 and 10 dollars an hour for this type of instruction, based on cost of living in the city.

In a situation where I will be charging full price, with adults I prepare a structured lesson the same way I do as a classroom teacher with a worksheet and geared towards whatever point of language the student wants to work on. With children who are taking extra tuition I build on what their school teacher is working on, make sure we get through their homework and build a better understanding with 1-on-1 teaching than they can get from a 20:1 or 40:1 student to teacher ratio they would have in the classroom. I typically charge between 15 and 25 dollars an hour for this type of lesson based on cost of living in the city.

@Murillo

If you click on your profile you will see an option to switch to "classic". I don't know how long they plan to have that option, but it is still a full functioning version of the site that you can use for now.

Myself, my favorite feature of the site was to search for language partners by city and make friends I will eventually have a chance to meet in real life. As far as I can see, you can only search my country on the new site, so I will be using classic as long as it's an option.

Living languages evolve and change over time. English in the UK and in the US have been evolving and changing independently of each other for hundreds of years. Portugal and Brazil speak different variants of Portuguese and the same is true of Spanish in Spain and in Latin American countries.

There is no ethical problem with teaching your children in a professional setting. I agree it could give rise to stressful situations and accusations of favoritism, but that could happen in any class. There are always students you enjoy teaching more than others, but as long as you provide the same education and opportunities to everyone it is not an ethical problem.

In my opinion, it's no problem in a classroom, the real problem would be in a coprorate situation where nepotism (giving preference to your family over other qualified candidates) actually does occur very often. If I am the CEO of a company deciding to give a promotion to either my own child or to you, that is unethical, only one of you can receive the promotion and you are at an unfair disadvantage. As a teacher, nothing about the education or grade I provide to one student should have any impact on another. There is no reason as a professor I could not give my own child an A that they deserved and give you an A that you had earned also. It is not a zero-sum situation.

As a teacher, I will add that I take steps to prevent myself from grading students unfairly. I do not have a place for students names at the beginning of an exam. They use 8-10 digit student ID numbers instead of their names, and their student ID sheet is the last page of my exams. I have graded, corrected and marked every paper before I know who it belongs to.

Achille's Heel

This morning, I listened to voa, from which I learnt a new phrase, "Achilles' heel".
For example: Failure to gain weight is my Achilles' heel.

Do you know where this phrase comes from and any other slang to express this meaning?