Some of us get text messages that are very serious business. Or in text speak, srs bsns.

But what makes a text go from light-hearted banter into draft UN Resolution? It would seem, the absence or presence of punctuation, such as full stops.

This phenomenon is called code-switching, the "practice of alternating between two or more languages or varieties of language in conversation."

Those of us with parents or grandparents born overseas will have seen this in action many times before. My Baba was notorious for speaking "Maso-lish", a mashup of Macedonian and English. My favourite was "Don't be a boudala," which means don't be an idiot. It would seem I was called that rather often. (Another favourite was "Otfori na computer", or "open the computer.") This isn't limited to multi-lingual people, however. We all do it.

Code-switching is almost seamless in terms of how we interpret language, and is controlled by our amygdala (lizard brains.). However when we expect short text messages or instant messages such as those over WhatsApp or Facebook Messenger, adding full stops, capital letters, etc. may break that implied code.

Many of us tend to believe a code-switch from informal (text speak) to formal language indicates a seriousness or gravitas to a conversation. Some of us just refuse to code-switch, employing the same tone and style across all mediums.

This requires some brainpower in realising your conversation partner isn't upset, being sarcastic, or whatever. Of course, much of what we mean when we type is lost, as we don't have visual and auditory cues such as facial expression, body language, and tonality. When in doubt, we can always Skype someone!