A colloquialism can relate to words, expressions or phrases that aren’t used in most formal written speech, though this can vary. They may also be called slang terms, though they aren’t necessarily slang in a negative sense, since it often isn’t rude to utter a colloquial term. These words may be specific to a region, or fall into popular style based on a variety of factors.
There are plenty of colloquialism examples in American speech. Many people would understand the phrase “What’s up?” as an informal question that expresses ideas like “Hi,” or “How are you?” or “What are you doing?” Individuals wouldn’t want to begin a business letter with this phrase, however, and it would probably be out of place in a letter to an older family member as well. Part of the problem with a phrase like “What’s up,” is that it is very vague, and its informality wouldn’t be suited to most formal writing, unless someone is writing fiction where it would make sense for a character to utter such a question.
Some terms and phrases come directly from the influence of a culture on language. For instance, texting has resulted in a number of abbreviated terms that are entering common usage. “OMG,” may be understood as “Oh My God,” and individuals may hear people, especially younger ones, utter the letters as much as they might say the whole phrase.
While Americans might easily understand what “OMG” means, they might have more trouble understanding certain words that are used in different regions of the US. Sometimes, a term takes on a specific usage that is tied to region and may not be easily recognizable elsewhere; these terms are occasionally called regionalisms. One of the most famous examples is how different regions of the US describe carbonated beverages: in some regions it is “pop,” while in others, it's “soda.”
Occasionally, pronunciation creates colloquial phrases. For instance, the term “creek” might be written or spoken as “crick” in certain parts of the US. This is not to be confused with the colloquialism where person has a “crick in the neck.”
Individuals may notice use of colloquial phrases even more profoundly if they speak American English and travel to someplace like Australia, where a new girl might be called a “nice Sheila," which could leave her grinning like a shot fox — in other words very happy. Moreover, someone might be called to babysit ankle biters (kids) on the trip. Visitors should just remember not to yabber too often (talk a lot), and not skite (boast) when meeting new people.
Even in a person's primarily language, the occasional colloquialism may be challenging to understand, but it can be much more difficult for people learning a new language. Plenty of colloquial words and phrases can make new language learners frustrated. This is particularly the case when a word is used in a way that is quite different from the dictionary definition.