National Character Sets
Different languages use different alphabets, especially when it comes to accented characters such as á à â ä ã. In fact there are many types of accents (a.k.a Diacritical Marks), the five most common being the ones just mentioned: Acute, Grave, Circumflex, Dieresis, and Tilde. For those five accents, there are corresponding alphabets, lower and upper case:
Entering Accented Characters
Different keyboards provide different ways in which to enter these accented characters. Nearly every keyboard layout that supports accented characters provides one or more "dead keys". These keys (e.g. a Dieresis (¨)), when pressed (sometimes with a modifier key such as Shift, Alt, or AltGR) do not display a character immediately, but wait for the next keystroke to complete the process. If (say) the next key is a capital U, then the key displayed is Ü. Many of the accented characters in the above list can be entered in this way.
Global Dead Keys
However, not all of the above accented characters are supported on keyboards in combination with their software drivers. To aid in entering all of the above accented letters, NARS2000 supports Global Dead Keys through its software drivers. For all of the NARS2000 built-in keyboard layouts (e.g., Danish, French, German, UK, and US), certain keystrokes have been reserved as Dead keys. The built-in keyboard layouts are divided into two classes: those that use the Alt key to enter APL characters and those that use the Ctl key. For those layouts in the former class, the reserved keystrokes are Ctl-Shift- with the letters a c d g t; the layouts in the latter class reserve Alt-Shift-a c d g t. The letters a c d g t correspond to the first letter of the accent: Acute, Circumflex, Dieresis, Grave, and Tilde. These choices may be overridden in case you need those keystrokes for your own purpose.
For example, to enter the letters ĵ or Ĵ on an Alt-type keyboard layout, press Ctl-Shift-c (for Circumflex), release those keys and then press either j to display ĵ or J to display Ĵ.
APL System Functions
From within APL, you have access to all of the above alphabets through the system functions ⎕á ⎕à ⎕â ⎕ä ⎕ã for the lowercase alphabets and ⎕Á ⎕À ⎕Â ⎕Ä ⎕Ã for the uppercase alphabets. Also, ⎕a and ⎕A return the unaccented alphabets.