Work with language tags and basic language associated data.
```rust // Language and Region are interned reference structures
let lng = Language::parse("en-US").unwrap(); println!("{}", lng.direction()); println!("{}", lng.nativename()); println!("{}", lng.internationalname()); println!("{}", lng.region().international_name());
// some regions are parsed as language assert!(Language::parse("us").unwrap() == Language::parse("en").unwrap());
// omitting region in language tag will supply a default region assert!(Language::parse("en-US").unwrap() == Language::parse("en").unwrap());
// invalid language if Language::parse("foozxc").is_none() { // procedure }
let region = Region::parse("us").unwrap(); println!("{}", region.international_name());
// invalid region if let None = Region::parse("foozxc") { // procedure } ```