I'm not aware of Access insisting on . for decimal anywhere.

Randy Birch has code to read locale numeric information at
http://vbnet.mvps.org/code/locale/localenumerics.htm

Obligatory warning: Randy's site is aimed at VB programmers. There are
significant differences between the controls available for forms in Access
and in VB, meaning that sometimes his code won't port directly to Access.
This is one of these cases. In VB, you write to a text box using its Text
property. In Access, you cannot use the Text property unless the control has
focus. You'll need to change statements such as:

  Text1.Text = GetUserLocaleInfo(LCID, LOCALE_SDECIMAL)
  Text2.Text = GetUserLocaleInfo(LCID, LOCALE_STHOUSAND)

to

  Me.Text1 = GetUserLocaleInfo(LCID, LOCALE_SDECIMAL)
  Me.Text2 = GetUserLocaleInfo(LCID, LOCALE_STHOUSAND)

Perhaps simpler, though, would be to include something like Mid(CStr(1/2),
2, 1) to determine what the decimal character is (although you could then
run into problems with , vs. ; in the Mid statement!)