Recognize that people wrongly think that turning up the volume somehow creates instant understanding. Avoid this common mistake (however, do not speak too quietly).
Do not cover or hide your mouth because listeners will want to watch you as you pronounce your words. This helps them figure out what you are saying in many cases.
Do not use baby talk or incorrect English. This does not make you easier to understand. It will confuse your listener and may give the wrong impression about your own level of competence.
Avoid running words together ( Do-ya wanna eat-a-pizza?). One of the biggest challenges for listeners is knowing where one word ends and the next one begins. Give them a small pause between words if they seem to be struggling.
When possible, opt for simple words instead of ones that are complex. The more basic a word is, the better the chance is that it will be understood. ("Big" is a better choice than "enormous" for example. "Make" is a better choice than "manufacture.") However, with a Romance language speaker (i.e. Spanish, French, Italian, Portuguese, Romanian), these 'complex' words can be useful as they are rooted in Latin.
Avoid verb phrases that sound very similar to non-native English speaker. "Look out" sounds very close to "look for." Both are similar to "look out for." Many times you can use another word in these cases. (Example: look out = be careful, look for = search for, look out for = watch for).
As much as possible, avoid using filler and colloquialisms ('um...', 'like...','Yeah, totally.') as non-native speakers, especially ones of lower proficiency levels, may get hung up on these thinking the filler language is vocabulary that they don't possess. Colloquialisms are likely to be unknown as well, especially if they are not easy to find in the dictionary.
If asked to repeat something, first repeat it as you said it the first time. Then again. It could be that they simply didn't hear you. If your listener still doesn't understand, however, change a few key words in the sentence. It may be that they couldn't understand one or two of the words. Also repeat the whole sentence and not just the last couple of words. It's time consuming, but it helps prevent confusion.
Consider the fact that your dialect may not be what the other person has learned in school. For example, most non-Americans expect the second t in the word "twenty" to be pronounced.
Paraphrase. if you happen to know a similar word to the word you are searching for then use it. As your knowledge of the foreign language builds this becomes even easier.
Avoid using contractions or short forms. Use long forms. “Can’t” is one word you must use the long form with. It is difficult for a non-native speaker to understand the difference between “can” and “can’t” in a sentence. For example, “I can’t take you on Friday” and “I can take you on Friday”. Use the long form, “cannot”. “I cannot take you on Friday”.
Decrease the use of words that fill your sentences. The idea is to remove the “noise” from your speech. Imagine trying to listen to the radio with two young children in the same room. They are playing and screaming. What is the result? "Family of...car...on vacation...in Arizona." If your oral communication is filled with "um", "like", "you know", or other fillers, comprehension is more difficult. “Right” is a word that commonly fills conversations. I prefer to use “Yes, that is correct”. A non-native speaker may not understand “right” and confuse it with its opposite, “left”.
Be explicit: Say “Yes” or “No”. Do not say: “Uh-huh” or “Uh-uh”. Those words are not in grammar books!
Listen and try not to form your response while the other person is talking. Wait until the person is done so that you can clarify if needed and give correct information based on all they have said.
Be aware that other cultures have different standards regarding touching, eye contact and personal space. Someone standing too close or not looking you in the eye is merely following their own cultural standard and not trying to offend.
Be patient and smile. The more relaxed you are, the more you are in control of your communication. Do not give a busy lifestyle or a meeting agenda permission to control your speech. Think as you speak and do not speak as you think.
- If you are having problems with verbal communication, try drawing an object on paper.
- If the other person did not understand what you said repeat it as you said it the first time
- If you have failed with a sentence, reflect on that sentence (did you unconsciously use a distracting metaphor, a colloquialism, conjunctions?). Try again with a new, simpler sentence free of complex language.
- Keep a good attitude and be friendly. Impatience will inhibit your ability to communicate and can alienate your listener.
- Making Requests: Even though you might be tempted to speak politely with indirect questions (ie. Would it be possible to..? I was wondering if you could..? If you wouldn't mind terribly to..? etc.), it is best to avoid as many unnecessary collocations as possible. A simple "can you X or Is it Y - followed with a universal "please" and "thank you" should do the trick.
- There is a nuance to not using big words: when speaking to a person who speaks a Western European language, the big words in English are more likely to be words that already exist in that person's language, so sometimes you might have more luck with the big words than the small ones.
- Speak a little slower than normal. It takes more time to parse a foreign language; give your listener that time. This goes along with being patient and articulating clearly.
- Make many more gestures than normal when speaking. Often it's possible to understand just by catching a couple of words and seeing the gestures.
- Write things down. It's sometimes easier to understand written language than spoken language.
- Get used to not understanding everything. Take guesses at what someone said in another language, unless it's important that you understand the details, e.g. buying a train ticket, doctors office, etc. For most daily situations, you can just guess, and the situation will work out. Of course some misunderstandings will result, but accept it and move on.
- If the person is new to English, keep in mind that on a certain level he will be "translating" his language to yours. His English words and expressions are influenced by his mother tongue, so things that might sound impolite to you are not always meant in that way. For example, a plain "No" might seem too blunt, whereas "I don't agree," if said politely, keeps open the door of communication. Try to listen "between the lines" before judging the other speaker's attitude.
- If you are still unable to communicate by any other means, try speaking even - more - slowly and even more distinctly to your listener (especially if you know you tend to mumble).
- Pocket electronic translators are the size of a calculator, can cost under $20 (check  and Sort low to high price), and translate common words and phrases. You can type in English, they can type in their language (with some challenge, since it's an English keyboard). Printed pocket sized two-language dictionaries are inexpensive.
- If all else fails, try finding another language that you are both comfortable with. For example, if the person you are speaking to is German, but is more fluent in French than in English (and your French is better than your German), you might have more success.