diff --git a/src/CutAndPaste.C b/src/CutAndPaste.C
index c2ddae5c60..d82aab8faa 100644
--- a/src/CutAndPaste.C
+++ b/src/CutAndPaste.C
@@ -649,7 +649,7 @@ void pasteSelection(LCursor & cur, ErrorList & errorList, size_t sel_index)
 
 
 // simple replacing. The font of the first selected character is used
-void replaceSelectionWithString(LCursor & cur, string const & str, bool backwards)
+void replaceSelectionWithString(LCursor & cur, docstring const & str, bool backwards)
 {
 	recordUndo(cur);
 	DocIterator selbeg = cur.selectionBegin();
@@ -661,10 +661,10 @@ void replaceSelectionWithString(LCursor & cur, string const & str, bool backward
 	// Insert the new string
 	pos_type pos = cur.selEnd().pos();
 	Paragraph & par = cur.selEnd().paragraph();
-	string::const_iterator cit = str.begin();
-	string::const_iterator end = str.end();
+	docstring::const_iterator cit = str.begin();
+	docstring::const_iterator end = str.end();
 	for (; cit != end; ++cit, ++pos)
-		par.insertChar(pos, (*cit), font, cur.buffer().params().trackChanges);
+		par.insertChar(pos, *cit, font, cur.buffer().params().trackChanges);
 
 	// Cut the selection
 	cutSelection(cur, true, false);
diff --git a/src/CutAndPaste.h b/src/CutAndPaste.h
index 332e414002..eb6aded2e2 100644
--- a/src/CutAndPaste.h
+++ b/src/CutAndPaste.h
@@ -44,7 +44,7 @@ void cutSelection(LCursor & cur, bool doclear, bool realcut);
  * the new string. When \c backwards == false, set anchor before
  * cursor; otherwise set cursor before anchor.
  */
-void replaceSelectionWithString(LCursor & cur, std::string const & str, 
+void replaceSelectionWithString(LCursor & cur, docstring const & str,
 				bool backwards);
 /// replace selection helper
 void replaceSelection(LCursor & cur);
diff --git a/src/SpellBase.C b/src/SpellBase.C
index b8b212b6a4..e2935de163 100644
--- a/src/SpellBase.C
+++ b/src/SpellBase.C
@@ -40,9 +40,9 @@ void SpellBase::accept(WordLangTuple const &)
 {}
 
 
-string const SpellBase::nextMiss()
+docstring const SpellBase::nextMiss()
 {
-	return string();
+	return docstring();
 }
 
 
diff --git a/src/SpellBase.h b/src/SpellBase.h
index f9f2a4a732..e4ec616bdc 100644
--- a/src/SpellBase.h
+++ b/src/SpellBase.h
@@ -15,8 +15,6 @@
 
 #include "support/docstring.h"
 
-#include <string>
-
 
 namespace lyx {
 
@@ -61,7 +59,7 @@ public:
 	virtual void accept(WordLangTuple const &);
 
 	/// return the next near miss after a SUGGESTED_WORDS result
-	virtual std::string const nextMiss();
+	virtual docstring const nextMiss();
 
 	/// give an error message on messy exit
 	virtual docstring const error();
diff --git a/src/WordLangTuple.h b/src/WordLangTuple.h
index 9e2232bd3d..b1a31bd90d 100644
--- a/src/WordLangTuple.h
+++ b/src/WordLangTuple.h
@@ -12,7 +12,7 @@
 #ifndef WORD_LANG_TUPLE_H
 #define WORD_LANG_TUPLE_H
 
-#include <string>
+#include "support/docstring.h"
 
 
 namespace lyx {
@@ -26,12 +26,12 @@ class WordLangTuple {
 public:
 	WordLangTuple() {}
 
-	WordLangTuple(std::string const & w, std::string const & c)
+	WordLangTuple(docstring const & w, std::string const & c)
 		: word_(w), code_(c)
 	{}
 
 	/// return the word
-	std::string const & word() const {
+	docstring const & word() const {
 		return word_;
 	}
 
@@ -42,7 +42,7 @@ public:
 
 private:
 	/// the word
-	std::string word_;
+	docstring word_;
 	/// language code of word
 	std::string code_;
 };
diff --git a/src/aspell.C b/src/aspell.C
index f9caa75233..631945c24f 100644
--- a/src/aspell.C
+++ b/src/aspell.C
@@ -87,14 +87,16 @@ ASpell::Result ASpell::check(WordLangTuple const & word)
 
 	AspellSpeller * m = it->second.speller;
 
-	int const word_ok = aspell_speller_check(m, word.word().c_str(), -1);
+	// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+	int const word_ok = aspell_speller_check(m, to_utf8(word.word()).c_str(), -1);
 	BOOST_ASSERT(word_ok != -1);
 
 	if (word_ok) {
 		res = OK;
 	} else {
+		// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
 		AspellWordList const * sugs =
-			aspell_speller_suggest(m, word.word().c_str(), -1);
+			aspell_speller_suggest(m, to_utf8(word.word()).c_str(), -1);
 		BOOST_ASSERT(sugs != 0);
 		els = aspell_word_list_elements(sugs);
 		if (aspell_word_list_empty(sugs))
@@ -110,7 +112,8 @@ void ASpell::insert(WordLangTuple const & word)
 {
 	Spellers::iterator it = spellers_.find(word.lang_code());
 	if (it != spellers_.end())
-		aspell_speller_add_to_personal(it->second.speller, word.word().c_str(), -1);
+		// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+		aspell_speller_add_to_personal(it->second.speller, to_utf8(word.word()).c_str(), -1);
 }
 
 
@@ -118,18 +121,20 @@ void ASpell::accept(WordLangTuple const & word)
 {
 	Spellers::iterator it = spellers_.find(word.lang_code());
 	if (it != spellers_.end())
-		aspell_speller_add_to_session(it->second.speller, word.word().c_str(), -1);
+		// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+		aspell_speller_add_to_session(it->second.speller, to_utf8(word.word()).c_str(), -1);
 }
 
 
-string const ASpell::nextMiss()
+docstring const ASpell::nextMiss()
 {
 	char const * str = 0;
 
 	if (els)
 		str = aspell_string_enumeration_next(els);
 
-	return (str ? str : "");
+	// FIXME UNICODE: str is not in UTF8, but probably the locale encoding
+	return (str ? from_utf8(str) : docstring());
 }
 
 
@@ -141,6 +146,7 @@ docstring const ASpell::error()
 		err = aspell_error_message(spell_error_object);
 	}
 
+	// FIXME UNICODE: err is not in UTF8, but probably the locale encoding
 	return (err ? from_utf8(err) : docstring());
 }
 
diff --git a/src/aspell_local.h b/src/aspell_local.h
index 1b45c70451..f7e840d5f4 100644
--- a/src/aspell_local.h
+++ b/src/aspell_local.h
@@ -15,8 +15,6 @@
 
 #include "SpellBase.h"
 
-#include "support/docstring.h"
-
 #include <map>
 
 
@@ -55,7 +53,7 @@ public:
 	virtual void accept(WordLangTuple const &);
 
 	/// return the next near miss after a SUGGESTED_WORDS result
-	virtual std::string const nextMiss();
+	virtual docstring const nextMiss();
 
 	/// give an error message on messy exit
 	virtual docstring const error();
diff --git a/src/frontends/controllers/ControlSpellchecker.C b/src/frontends/controllers/ControlSpellchecker.C
index d5e1fdb86d..c001bd27b4 100644
--- a/src/frontends/controllers/ControlSpellchecker.C
+++ b/src/frontends/controllers/ControlSpellchecker.C
@@ -173,7 +173,7 @@ WordLangTuple nextWord(LCursor & cur, ptrdiff_t & progress)
 			if (inword)
 				if (!word.empty() && !ignoreword) {
 					cur.setSelection();
-					return WordLangTuple(lyx::to_utf8(word), lang_code);
+					return WordLangTuple(word, lang_code);
 				} else
 					inword = false;
 		}
@@ -182,7 +182,7 @@ WordLangTuple nextWord(LCursor & cur, ptrdiff_t & progress)
 		++progress;
 	}
 
-	return WordLangTuple(string(), string());
+	return WordLangTuple(docstring(), string());
 }
 
 } // namespace anon
@@ -243,7 +243,7 @@ void ControlSpellchecker::check()
 			return;
 	}
 
-	lyxerr[Debug::GUI] << "Found word \"" << getWord() << "\"" << endl;
+	lyxerr[Debug::GUI] << "Found word \"" << to_utf8(getWord()) << "\"" << endl;
 
 	int const size = cur.selEnd().pos() - cur.selBegin().pos();
 	cur.pos() -= size;
@@ -297,10 +297,10 @@ void ControlSpellchecker::showSummary()
 }
 
 
-void ControlSpellchecker::replace(string const & replacement)
+void ControlSpellchecker::replace(docstring const & replacement)
 {
 	lyxerr[Debug::GUI] << "ControlSpellchecker::replace("
-			   << replacement << ")" << std::endl;
+			   << to_utf8(replacement) << ")" << std::endl;
 	BufferView & bufferview = *kernel().bufferview();
 	cap::replaceSelectionWithString(bufferview.cursor(), replacement, true);
 	kernel().buffer().markDirty();
@@ -312,7 +312,7 @@ void ControlSpellchecker::replace(string const & replacement)
 }
 
 
-void ControlSpellchecker::replaceAll(string const & replacement)
+void ControlSpellchecker::replaceAll(docstring const & replacement)
 {
 	// TODO: add to list
 	replace(replacement);
@@ -326,13 +326,13 @@ void ControlSpellchecker::insert()
 }
 
 
-string const ControlSpellchecker::getSuggestion() const
+docstring const ControlSpellchecker::getSuggestion() const
 {
 	return speller_->nextMiss();
 }
 
 
-string const ControlSpellchecker::getWord() const
+docstring const ControlSpellchecker::getWord() const
 {
 	return word_.word();
 }
diff --git a/src/frontends/controllers/ControlSpellchecker.h b/src/frontends/controllers/ControlSpellchecker.h
index 4f99f6d892..6b19f66175 100644
--- a/src/frontends/controllers/ControlSpellchecker.h
+++ b/src/frontends/controllers/ControlSpellchecker.h
@@ -45,10 +45,10 @@ public:
 	virtual bool exitEarly() const { return exitEarly_; }
 
 	/// replace word with replacement
-	void replace(std::string const &);
+	void replace(docstring const &);
 
 	/// replace all occurances of word
-	void replaceAll(std::string const &);
+	void replaceAll(docstring const &);
 
 	/// insert word in personal dictionary
 	void insert();
@@ -61,10 +61,10 @@ public:
 	void check();
 
 	/// get suggestion
-	std::string const getSuggestion() const;
+	docstring const getSuggestion() const;
 
 	/// get word
-	std::string const getWord() const;
+	docstring const getWord() const;
 
 	/// returns progress value
 	int getProgress() const { return oldval_; }
diff --git a/src/frontends/qt4/QSpellchecker.C b/src/frontends/qt4/QSpellchecker.C
index a07dbeb98d..30bc8cb4d5 100644
--- a/src/frontends/qt4/QSpellchecker.C
+++ b/src/frontends/qt4/QSpellchecker.C
@@ -72,7 +72,7 @@ void QSpellchecker::ignore()
 
 void QSpellchecker::replace()
 {
-	controller().replace(fromqstr(dialog_->replaceCO->currentText()));
+	controller().replace(qstring_to_ucs4(dialog_->replaceCO->currentText()));
 }
 
 
@@ -91,7 +91,7 @@ void QSpellchecker::partialUpdate(int s)
 		dialog_->wordED->setText(toqstr(controller().getWord()));
 		dialog_->suggestionsLW->clear();
 
-		string w;
+		docstring w;
 		while (!(w = controller().getSuggestion()).empty()) {
 			dialog_->suggestionsLW->addItem(toqstr(w));
 		}
diff --git a/src/ispell.C b/src/ispell.C
index ab7dfcb89c..87613ade36 100644
--- a/src/ispell.C
+++ b/src/ispell.C
@@ -252,7 +252,7 @@ ISpell::ISpell(BufferParams const & params, string const & lang)
 		return;
 	}
 
-	/* Parent process: Read ispells identification message */
+	// Parent process: Read ispells identification message
 
 	bool err_read;
 	bool error = select(err_read);
@@ -264,7 +264,8 @@ ISpell::ISpell(BufferParams const & params, string const & lang)
 			return;
 		}
 
-		/* must have read something from stderr */
+		// must have read something from stderr
+		// FIXME UNICODE: buf is not in UTF8, but probably the locale encoding
 		error_ =from_utf8(buf);
 	} else {
 		// select returned error
@@ -343,18 +344,19 @@ bool ISpell::select(bool & err_read)
 }
 
 
-string const ISpell::nextMiss()
+docstring const ISpell::nextMiss()
 {
 	// Well, somebody is a sick fuck.
 
 	if (str == 0 || *(e+1) == '\0')
-		return "";
+		return docstring();
 	char * b = e + 2;
 	e = strpbrk(b, ",\n");
 	*e = '\0';
 	if (b)
-		return b;
-	return "";
+		// FIXME UNICODE: b is not in UTF8, but probably the locale encoding
+		return from_utf8(b);
+	return docstring();
 }
 
 
@@ -370,7 +372,8 @@ enum ISpell::Result ISpell::check(WordLangTuple const & word)
 
 	Result res;
 
-	::fputs(word.word().c_str(), out);
+	// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+	::fputs(to_utf8(word.word()).c_str(), out);
 	::fputc('\n', out);
 
 	bool err_read;
@@ -382,6 +385,7 @@ enum ISpell::Result ISpell::check(WordLangTuple const & word)
 	}
 
 	if (err_read) {
+		// FIXME UNICODE: buf is not in UTF8, but probably the locale encoding
 		error_ = from_utf8(buf);
 		return UNKNOWN_WORD;
 	}
@@ -434,7 +438,8 @@ enum ISpell::Result ISpell::check(WordLangTuple const & word)
 void ISpell::insert(WordLangTuple const & word)
 {
 	::fputc('*', out); // Insert word in personal dictionary
-	::fputs(word.word().c_str(), out);
+	// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+	::fputs(to_utf8(word.word()).c_str(), out);
 	::fputc('\n', out);
 }
 
@@ -442,7 +447,8 @@ void ISpell::insert(WordLangTuple const & word)
 void ISpell::accept(WordLangTuple const & word)
 {
 	::fputc('@', out); // Accept in this session
-	::fputs(word.word().c_str(), out);
+	// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+	::fputs(to_utf8(word.word()).c_str(), out);
 	::fputc('\n', out);
 }
 
diff --git a/src/ispell.h b/src/ispell.h
index 0fe77a15bc..613c9d208c 100644
--- a/src/ispell.h
+++ b/src/ispell.h
@@ -47,7 +47,7 @@ public:
 	virtual void accept(WordLangTuple const & word);
 
 	/// return the next near miss after a SUGGESTED_WORDS result
-	virtual std::string const nextMiss();
+	virtual docstring const nextMiss();
 
 	/// give an error message on messy exit
 	virtual docstring const error();
diff --git a/src/lyxfind.C b/src/lyxfind.C
index 98f30e15d3..93797a6159 100644
--- a/src/lyxfind.C
+++ b/src/lyxfind.C
@@ -218,7 +218,7 @@ bool stringSelected(BufferView * bv, string const & searchstr,
 
 
 int replace(BufferView * bv, string const & searchstr,
-	    string const & replacestr, bool cs, bool mw, bool fw)
+	    std::string const & replacestr, bool cs, bool mw, bool fw)
 {
 	if (!searchAllowed(bv, searchstr) || bv->buffer()->isReadonly())
 		return 0;
@@ -227,7 +227,7 @@ int replace(BufferView * bv, string const & searchstr,
 		return 0;
 
 	LCursor & cur = bv->cursor();
-	cap::replaceSelectionWithString(cur, replacestr, fw);
+	cap::replaceSelectionWithString(cur, from_utf8(replacestr), fw);
 	bv->buffer()->markDirty();
 	find(bv, searchstr, cs, mw, fw);
 	bv->update();
diff --git a/src/pspell.C b/src/pspell.C
index 9d876c1ff8..042161efb7 100644
--- a/src/pspell.C
+++ b/src/pspell.C
@@ -97,14 +97,16 @@ enum PSpell::Result PSpell::check(WordLangTuple const & word)
 
 	PspellManager * m = it->second.manager;
 
-	int word_ok = pspell_manager_check(m, word.word().c_str());
+	// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+	int word_ok = pspell_manager_check(m, to_utf8(word.word()).c_str());
 	BOOST_ASSERT(word_ok != -1);
 
 	if (word_ok) {
 		res = OK;
 	} else {
+		// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
 		PspellWordList const * sugs =
-			pspell_manager_suggest(m, word.word().c_str());
+			pspell_manager_suggest(m, to_utf8(word.word()).c_str());
 		BOOST_ASSERT(sugs != 0);
 		els = pspell_word_list_elements(sugs);
 		if (pspell_word_list_empty(sugs))
@@ -120,7 +122,8 @@ void PSpell::insert(WordLangTuple const & word)
 {
 	Managers::iterator it = managers_.find(word.lang_code());
 	if (it != managers_.end())
-		pspell_manager_add_to_personal(it->second.manager, word.word().c_str());
+		// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+		pspell_manager_add_to_personal(it->second.manager, to_utf8(word.word()).c_str());
 }
 
 
@@ -128,19 +131,21 @@ void PSpell::accept(WordLangTuple const & word)
 {
 	Managers::iterator it = managers_.find(word.lang_code());
 	if (it != managers_.end())
-		pspell_manager_add_to_session(it->second.manager, word.word().c_str());
+		// FIXME UNICODE: we don't need to convert to UTF8, but probably to the locale encoding
+		pspell_manager_add_to_session(it->second.manager, to_utf8(word.word()).c_str());
 }
 
 
-string const PSpell::nextMiss()
+docstring const PSpell::nextMiss()
 {
 	char const * str = 0;
 
 	if (els)
 		str = pspell_string_emulation_next(els);
 	if (str)
-		return str;
-	return "";
+		// FIXME UNICODE: str is not in UTF8, but probably the locale encoding
+		return from_utf8(str);
+	return docstring();
 }
 
 
diff --git a/src/pspell.h b/src/pspell.h
index 7d2cfc14ef..44071dc3e1 100644
--- a/src/pspell.h
+++ b/src/pspell.h
@@ -53,7 +53,7 @@ public:
 	virtual void accept(WordLangTuple const &);
 
 	/// return the next near miss after a SUGGESTED_WORDS result
-	virtual std::string const nextMiss();
+	virtual docstring const nextMiss();
 
 	/// give an error message on messy exit
 	virtual docstring const error();