Not reallly. This sounds a little off. The word “delay” is usually used when we refer to projects, transport, processes etc. When you can’t complete a task in time (in this case to reply to an email), I would suggest other forms such as:

• My apologies for answering late.
• I am sorry for answering late.
• My apologies for not answering earlier.

A student’s question: 

I usually use this form to ask about someone’s availability for a meeting:

“Do you have availability next Tuesday?” Is it correct?

My answer:

Well, I would not say it’s incorrect, but it sounds quite unusual to use “availability” this way. When asking about people’s timetables, the following would sound better: 

• Are you available on Tuesday 20th?
• Would Tuesday 20th be good?
• Can you do Tuesday 20th?

Observe how “good” and “do”, which are basic and simple words, are used in business communication when confirming timetables and.

Note: If you want to use the word “availability”, then “What is your availability next week?” is the way to ask (instead of “Do you have availability …”).

Spanish “somos” and English “we are” can have different uses.

Somos profesores. (job/description of people)

Somos tres. (number of people)

In English “We are + a number” usually means “We are _______  years old“. 

We are teachers. (job/description of people)

We are 20. (age)

So, saying “We are 20 in the group” sounds strange a little if you mean the number of people.

If your focus is the number of people, you could say:

There are 20 people in the group.

If you want to include yourself in the group (Spanish “Somos 20 en el grupo”):

 We are a goup of 20 people. / There are 20 of us in the group.

Note: if your focus is not the number of people but a definition (description) of the people you mention, then it’s fine to say “we are”, like in this example:

We are three math teachers who also like music and dancing.

This one is often heard in other expressions too. The problem is simple: in Spanish the word “no” is often used after mentioning what it refers to: “Comes fruta?” – “Bueno, cada día no.”

In English it is more common to do it the other way around, plus the word to use to express the negative in this case is “not”.

– How often do you eat fruit?
– Well … not every day.

Here is another example:

– Is there a shopping centre near here?”
– Not in this town, but there’s a new one in the next town, about a 10 minute drive from here.”

When an activity or a place is fun, it means you enjoy doing it or being there. That is you have a good time.

For example:

Playing board games is fun. / I like reading about dinosaurs. My friends find it boring, but I think it’s fun.

When something is funny, it makes you laugh. It means that it is humorous.

For example:

This is a funny story. / She is a funny person. / What a funny situation!