The normalization of UNICODE3 accented chars in free-text index can be controlled by setting up the configuration parameter XAnyNormalization in the virtuoso.ini config file, section [I18N]. This parameter controls whether accented UNICODE characters should be converted to their non-accented base variants at the very beginning of free-text indexing or parsing a free-text query string. The parameter's value is an integer that is bitmask with only 2 bits in use atm:

  1. 0: the default behavior, do not normalize anything, so "Jose" and "José" are two distinct words.

  2. 2: Any combined char is converted to its (smallest known) base. So "é" will lose its accent and become plain old ASCII "e".

  3. 3: This is equl to 1|2 and when set then performs both conversions. As a result, pair of base char and combinig char loses its second char and chars with accents will lose accents.

If the parameter is required at all, the needed value is probably 3. So the fragment of virtuoso.ini is:

[I18N]
XAnyNormalization=3

In some seldom case the value of 1 can be appropriate. The parameter should be set once before creating the database. If changed on the existing database, all free-text indexes that may contain non-ASCII data should be re-created. On a typical system, the parameter affects all text columns, XML columns, RDF literals and queries.

Strictly speaking, it affects not all of them but only items that use default "x-any" language or language derived from x-any such as "en" and "en-US" but if you haven't tried writing new C plugins for custom languages you should not look so deep.

As an example, with XAnyNormalization=3 once can get the following:

SQL>SPARQL

INSERT IN <http://InternationalNSMs/>
   { <s> <sp> "Índio João Macapá Júnior Tôrres Luís Araújo José" ;
     <ru> "&#1054;&#1085; &#1076;&#1086;&#1073;&#1072;&#1074;&#1080;&#1083; &#1082;&#1072;&#1088;&#1090;&#1086;&#1096;&#1082;&#1080;, &#1087;&#1086;&#1089;&#1086;&#1083;&#1080;&#1083; &#1080; &#1087;&#1086;&#1089;&#1090;&#1072;&#1074;&#1080;&#1083; &#1072;&#1082;&#1074;&#1072;&#1088;&#1080;&#1091;&#1084; &#1085;&#1072; &#1086;&#1075;&#1086;&#1085;&#1100;" . }

INSERT INTO <http://InternationalNSMs/>, 2 (or less) triples -- done

SQL> DB.DBA.RDF_OBJ_FT_RULE_ADD (null, null, 'InternationalNSMs.wb');

Done. -- 0 msec.

SQL>vt_inc_index_db_dba_rdf_obj();

Done. -- 26 msec.

SQL>SPARQL
SELECT *
FROM <http://InternationalNSMs/>
WHERE
  {
    ?s ?p ?o
  }
ORDER BY ASC (str(?o))

s  sp  Índio João Macapá Júnior Tôrres Luís Araújo José
s  ru  &#1054;&#1085; &#1076;&#1086;&#1073;&#1072;&#1074;&#1080;&#1083; &#1082;&#1072;&#1088;&#1090;&#1086;&#1096;&#1082;&#1080;, &#1087;&#1086;&#1089;&#1086;&#1083;&#1080;&#1083; &#1080; &#1087;&#1086;&#1089;&#1090;&#1072;&#1074;&#1080;&#1083; &#1072;&#1082;&#1074;&#1072;&#1088;&#1080;&#1091;&#1084; &#1085;&#1072; &#1086;&#1075;&#1086;&#1085;&#1100;

2 Rows. -- 2 msec.

SQL> SPARQL
SELECT *
FROM <http://InternationalNSMs/>
WHERE
  {
    ?s ?p ?o . ?o bif:contains "'Índio João Macapá Júnior Tôrres Luís Araújo José'" .
  }

s  sp  Índio João Macapá Júnior Tôrres Luís Araújo José

1 Rows. -- 2 msec.

SQL>SPARQL
SELECT *
FROM <http://InternationalNSMs/>
WHERE
  {
    ?s ?p ?o . ?o bif:contains "'Indio Joao Macapa Junior Torres Luis Araujo Jose'" . }

s  sp  Índio João Macapá Júnior Tôrres Luís Araújo José

1 Rows. -- 1 msec.

SQL> SPARQL
SELECT *
FROM <http://InternationalNSMs/>
WHERE
  {
    ?s ?p ?o . ?o bif:contains "'&#1087;&#1086;&#1089;&#1090;&#1072;&#1074;&#1080;&#1083; &#1072;&#1082;&#1074;&#1072;&#1088;&#1080;&#1091;&#1084; &#1085;&#1072; &#1086;&#1075;&#1086;&#1085;&#1100;'" . }

s  ru  &#1054;&#1085; &#1076;&#1086;&#1073;&#1072;&#1074;&#1080;&#1083; &#1082;&#1072;&#1088;&#1090;&#1086;&#1096;&#1082;&#1080;, &#1087;&#1086;&#1089;&#1086;&#1083;&#1080;&#1083; &#1080; &#1087;&#1086;&#1089;&#1090;&#1072;&#1074;&#1080;&#1083; &#1072;&#1082;&#1074;&#1072;&#1088;&#1080;&#1091;&#1084; &#1085;&#1072; &#1086;&#1075;&#1086;&#1085;&#1100;

There was also request for function that normalizes characters in strings as free-text engine will do with XAnyNormalization=3 , the function will be provided as a separate patch and depends on this specific patch.