If you edit a template you may be tempted to just place static text into the template. For example you are putting in a title div into the document like this:
<div class="ucColorSubHeader">Your contact email</div>
If you enter text directly like this into the template, it will generate an i18n (internationalization) violation. An i18n violation means there is a piece of text that the system can not automatically translate when the customer is browsing in a different language. To get around this problem, the text is passed through the i18n system so that it can be tracked and translated. To do this, use the $i18n object by calling $i18n.write like the example below.
<div class="ucColorSubHeader">$i18n.write("checkout.viewcart.yourContactEmailField", "Your contact email")</div>
Notice that there are two parameters on this $i18n.write call. The first parameter is a "key" and then the second parameter is the text. Every single write call needs to have a unique key associated with it. The key is arbitrary, but you will typically see a three part key used by our theme developers: section.template.textIdentifier.