While speaking

1. Think aloud

If you are thinking “That’s a difficult question”, “I’ve never really thought about that before”, “I’m not sure that I could even explain in my own language” or “I really don’t know what my answer to that question is”, then that is exactly what you should say. Not only does following this tip fill silence, but you’ll often find that by the time you’ve finished saying that initial thought you’ve actually thought of at least some way of answering the question.

2. Start speaking, then think about what you are going to say

This is related to thinking aloud above and to learning sentence starters, mentioned below. Phrases which can start lots of sentences and are long enough to give you thinking time include “In my limited experience,…”, “I have generally found that,…”, “From my point of view,…”, “I don’t have any strong views about this one way or the other, but…”, “Off the top of my head,…”, “My initial answer would be…” and “The first thing that springs to mind is…”

3. Fill silence

This is related to the two things above but is a much easier thing to keep in mind – fill all silence with something or the other, even it is just sounds like “um” and “err”, extending some words while you think of others (“It was kiiiiiiind of aaaaa…”), echoing back the question or statement that you are responding to, or commenting on it before you make your own contribution (“That’s a difficult/ an unusual/ an interesting question”, etc).

4. Send the turn back

This is really only an emergency measure that could interfere with developing your fluency if you use it too much, but one way of avoiding uncomfortable silences is to ask something to the other person to give yourself time to think of what you want to say. The most natural way of doing this is to check the meaning of their question or previous statement with questions like “I’m not sure what… means”. This can be done fairly naturally even if you do understand what they want from you if you use questions to double check like “Do you mean…(or…)?”, “Are you asking me…?”, “Just to double check,…” and “So, if I understand you correctly you want to know…”

5. Use words from your language, then explain them

A lot of people get stuck when they think of a word in their own language which they can’t (quickly) translate into English. The easiest way around this is to mention the word in your own language and then explain it using phrases like “I don’t know how to say it in English but in my language we say ‘….’, which means something like…” and “There is an expression in my language ‘…’ which is something like…”

6. Use vague language

Native speakers often give themselves thinking time by saying things like “something like”, “or something like that”, “I suppose”, etc, even when in fact they are fairly or very sure about what they are saying. Other useful phrases to do this with include “I guess”, “more or less”, “You could say”, “I’d probably say” and “or so I’d imagine”.

7. Give provisional answers

One way to prompt yourself to speak before thinking too much is to always remember that you can change your mind later. Useful phrases when this might be the case include “Off the top of my head,…”, “The first thing that springs to mind is…”, “As far as I remember,…”, “I’ll check if this is really true but…” and “I’ve got the actual information elsewhere but…”

8. Really priorities fluency while speaking

It’s incredibly difficult to improve fluency and other things at the same time, so if you really want to improve how quickly and smoothly you speak, you have to put other things on the back burner. This particularly means not concentrating on accuracy, be that accurate grammar, perfect pronunciation, getting the level of politeness exactly right, or saying exactly what you mean to say.

9. Accept other weaknesses

This is another way of putting the point above. If you are going to speak more smoothly than usual, it will inevitably lead to grammar mistakes, more L1 interference in your pronunciation, less complex vocabulary, etc, so just accept that and work on those another time when they become your priorities.
10. Use the language you know to say what you can
… rather than trying to explain exactly the ideas in your head. At the most extreme level this can include agreeing when you really have the opposite opinion just because agreeing is easier or saying “It’s something like an English bungalow” when you know it isn’t that much like it at all (if a more accurate description doesn’t really matter).