I'd like to have a canonical place to pool information about Unicode support in various languages. Is it a part of the core language? Is it provided in libraries? Is it not available at all? Is there a resource popular resource for Unicode information in a language? One language per answer please. Also if you could make the language a heading that would make it easier to find.
Delphi 2009 fully supports Unicode. They've changed the implementation of string to default to 16-bit Unicode encoding, and most libraries including the third party ones support Unicode. See Marco Cantù's Delphi and Unicode.
Prior to Delphi 2009, the support for Unicode was limited, but there was WideChar and WideString to store the 16-bit encoded string. See Unicode in Delphi for more info.
Note, you can still develop bilingual CJKV application without using Unicode. For example, Shift JIS encoded string for Japanese can be stored using plain AnsiString.
Tcl strings have been sequences of Unicode characters since Tcl 8.1 (1999). Internally, they are morphed dynamically between UTF-8 (strictly the same Modified UTF-8 as Java due to the handling of U+00000 characters) and UCS-2 (in host endianness and BOM, of course). All external strings (with one exception), including those used to communicate with the OS, are internally Unicode before being transformed into whatever encoding is required for the host (or is manually configured on a communications channel). The exception is for where data is copied between two communications channels with a common encoding (and a few other restrictions not germane here) where a direct copy-free binary transfer is used.
Characters outside the BMP are not currently handled either internally or externally. This is a known issue.