How does the browser/rendering engine know where to hypenate a word?

In my CSS, I am using the following snippet of code:

word-break: break-word;
-webkit-hyphens: auto;
hyphens: auto;

How does the rendering engine know where to cut off a word in all the different languages? In Dutch, it's flawless, like a native speaker would hyphenate.

Solution

From the W3c spec

CSS Text Level 3 does not define the exact rules for hyphenation, however UAs are strongly encouraged to optimize their line-breaking implementation to choose good break points and appropriate hyphenation points. Hyphenation opportunities are considered when calculating ‘min-content’ intrinsic sizes.

and

Correct automatic hyphenation requires a hyphenation resource appropriate to the language of the text being broken. The UA is therefore only required to automatically hyphenate text for which the author has declared a language (e.g. via HTML lang or XML xml:lang) and for which it has an appropriate hyphenation resource.

So, basically, each broswer implements their own definitions of where hyphens should be placed. Combined multilingual dictionaries which are probably proprietary.