Technically, since Liberation Sans and Arial are default options on some platforms, just indicating the "sans-serif" generic family may be even better than specifying a list of default fonts such as "Helvetica, Arial Liberation Sans, Sans-Serif" (
more about this here).
From the design perspective, it is good to have visual consistency across platforms and languages (especially when content in different scripts may appear together). No font family I know of will meet both:
- Platform availability is not a big issue IMHO, webfonts can be used to deliver 92% of users would be able to use the selected font (according to this) and the rest of users will fallback to their system default for "sans-serif". Using webfonts has some extra cost but I am assuming that we are getting a benefit in terms of readability in the chosen font compared to the default system one that makes it worth using it.
- Language availability is a bigger problem. Which even with webfonts cannot be always solved due to lack of distributable fonts. The Noto font family created by Google has the goal of providing visual harmonization (e.g., compatible heights and stroke thicknesses) across multiple languages which makes it a good candidate in terms of cross-language consistency. The list of supported scripts is large compared to others (e.g., see Adobe Source Pro roadmap) but not complete yet.
Pau