What will you call the teacher who teaches you English - English teacher or teacher of English?

You may say that both are correct. When you say so, I definitely side with you. But while teacher of English creates no ambiguity, English teacher is ambiguous. An English teacher may either be a teacher who teaches English or a teacher who is an Englishman or woman.

You should always try to avoid the uses of ambiguous words.

In India the phrases black money and white money are widely used to mean 'illegally earned money' and 'legally earned money' respectively. If you look up these phrases in dictionaries, you will not see them in any of them because such phrases do not exist in real English. The word black and white collocate with tea and coffee (we can say black tea or white tea) but they do not collocate with money. 

Likewisewise, Indians drink strong tea and light tea. Strong tea is used in real English as strong collocates with tea but light tea is not used in real English as light does not collocate with tea. What Indians call light tea is known as weak tea in Britain and America. 

The word biblical means 'relating to the Bible' or 'in the Bible'. But if you know a girl or a woman in the biblical sense, it means that you have had sex with her. Remember that the idiom know someone in the biblical sense means 'to have had sex with someone'. You can also use way in place of sense.

There are several types of marriage, one of them being a shotgun marriage. Have you heard of such a word?

A wedding into which one or both partners are coerced, usually because the woman is pregnant is called a shotgun marriage or shotgun wedding.

This is an informal word. 

The father of the girl who became pregnant out of wedlock might threaten the man who was responsible for her pregnancy into marrying her by saying that he (father) would shoot him (the man responsible) to death unless he married her. From this the word might have originated.

Years back when I was walking along a road in Kannur Town (Kannur is a district in Kerala State, India), I heard a roadside seller of books say "All of you know that the act of self-killing is called suicide, but do you know what a self-killer is caller? I am sure you dunno. Never mind. Here's a book that teaches you such words."

Yes, every one of you know that killing oneself is called suicide, but what is the word for a killer who kills himself or herself?

It is also suicide. Yes, this word has two meanings. One is the common 'self-killing' and the other is the not so common 'self-killer'.

In India, especially in Kerala (a state of India), people use the word headweight to mean 'arrogance'. But in real English, (in British English or American English) you will not hear or see such a word. Even in dictionaries you will not see this word. This word was coined by some Keralite by word-for-word translation of the Malayalam word (Malayalam is the native tongue of Kerala) thalakanam. In Malayalam thalakanam means 'arrogance'. Thala means 'head' and kanam means 'weight'.

I would like to know what question tag you will use for the following sentences:

She and you are responsible for the loss,

Let me see the film,

Let us go and see the film tonight,

You know what STRONG TEA is. The tea that is not strong is called LIGHT TEA in India, especially in Kerala. But they do not know that the word LIGHT does not collocate with TEA. You know that WEAK is the opposite of STRONG. The same WEAK actually collocates with TEA. Yes, you can say WEAK TEA, not LIGHT TEA.

From ordinary dictionaries you will not get information about collocations. To learn which word should be used with which word, you must depend on collocations dictionary. The best one of this genre is OXFORD COLLOCATIONS DICTIONARY.

Recently I read in a book written by a Professor of English that the question tag for Let me read the letter is shall I? I would like to know whether any Englishman agrees with this. What I have learnt is that will you? should be used with the above sentence.

In India trains come to a stop on the platform. You can hear the announcement like this: Train No. ...... Parasuram Express from Mangalore to Trivandrum will shortly arrive on platform number one. But in England and America trains arrive at the platform. What about your country?