In LibreOffice 4.3 the user will be able to specify an arbitrary valid BCP47 language tag for text attribution.
In character attribution dialogs the language list box (of the Western text font if CJK or CTL are enabled) is now a combo box with an edit field where the user can specify a valid BCP 47 language tag to define a text language attribute if the language she wants to assign is not available from the selectable list. The input is checked against a copy of the IANA language-subtag-registry (transformed to XML), provided either with the liblangtag package of your OS distribution, or the liblangtag shipped with LibreOffice on systems that do not provide one. The internal registry file distributed with LibreOffice 4.3 consists of data as of 2014-04-10.
The language tag combo box with sga-Ogam entered, a tag for Irish, Old (to 900) written in Ogham script.
In LibreOffice 4.3 the user will be able to select how textual cell content shall be treated in arithmetic operations.
This setting determines how to treat text when encountered as operand in an arithmetic
operation or as argument to a function that expects a number instead.
Selectable under Tools → Options → LibreOffice Calc → Formula
in Detailed calculation settings → Custom → Details
from Conversion from text to number are:
Generate #VALUE! error
=1+"1" or =1+"x" give #VALUE!
Treat as zero
=1+"1" or =1+"x" give 1
Convert only unambiguous
=1+"1" gives 2, but =1+"1.000" or =1+"x" give #VALUE!
Convert also locale dependent
=1+"1.000" may be 2 or 1001 ... =1+"x" gives #VALUE!
For Generate #VALUE! error and Treat as zero,
setting the Treat empty string as zero option is disabled and the option is aligned to these settings,
for Convert only unambiguous and Convert also locale dependent
the Treat empty string as zero option can be set independently.
When reading documents created by other spreadsheet applications or older
versions of LibreOffice, and to interchange documents between different locales,
the Convert only unambiguous with Treat empty string as zero = True setting
is recommended, though LibreOffice so far acted as Convert also locale dependent with
Treat empty string as zero = False, which is the reason that option is kept as default.
The best setting to create new documents that can be interpreted by all
spreadsheet applications without on-the-fly string conversion is
Generate #VALUE! error. With this option enabled possible data errors can be spotted early.
Not having to convert strings during calculation is also faster, of course.