> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# BaseLanguageLetterSetEnum

BaseLanguageLetterSetEnum enumeration constants are used to describe different letter sets of a base language. Letter sets are the sets of characters that are allowed or prohibited in certain places inside the words in a specified language.

```
typedef enum {
 BLLS_Alphabet,
 BLLS_Prefixes,
 BLLS_Suffixes,
 BLLS_IgnorableLetters,
 BLLS_SubscriptAlphabet,
 BLLS_SuperscriptAlphabet
} BaseLanguageLetterSetEnum;
```

## Elements

| Name                        | Description                                                                                                                                                               |
| --------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| BLLS\\\_Alphabet            | This value denotes a letter set that includes the full alphabet of the base language.                                                                                     |
| BLLS\\\_IgnorableLetters    | This value denotes a letter set that includes the characters that may be found inside a word, but are ignored during the internal spelling check.                         |
| BLLS\\\_Prefixes            | This constant denotes a letter set that covers the punctuation marks that may be found immediately before words. Among these characters there may be ", (, \{ and so on.  |
| BLLS\\\_SubscriptAlphabet   | This value denotes a letter set that includes the characters allowed inside the words of the language as subscripts.                                                      |
| BLLS\\\_Suffixes            | This constant denotes a letter set that covers the punctuation marks that may be found immediately after words. Among these characters there may be !, ", ), } and so on. |
| BLLS\\\_SuperscriptAlphabet | This value denotes a letter set that includes the characters allowed inside the words of the language as superscripts.                                                    |

## Used in

[IBaseLanguage::LetterSet](/fine-reader/engine/api-reference/language-related-objects/baselanguage/letterset-property)