diff --git a/src/spell.h b/src/spell.h
new file mode 100644
index 0000000..e395059
--- /dev/null
+++ b/src/spell.h
@@ -0,0 +1,319 @@
+/* vi:set ts=8 sts=4 sw=4:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+
+/*
+ * spell.h: common code for spell checking, used by spell.c and spellfile.c.
+ */
+
+/* Use SPELL_PRINTTREE for debugging: dump the word tree after adding a word.
+ * Only use it for small word lists! */
+#if 0
+# define SPELL_PRINTTREE
+#endif
+
+/* Use SPELL_COMPRESS_ALLWAYS for debugging: compress the word tree after
+ * adding a word.  Only use it for small word lists! */
+#if 0
+# define SPELL_COMPRESS_ALLWAYS
+#endif
+
+/* Use DEBUG_TRIEWALK to print the changes made in suggest_trie_walk() for a
+ * specific word. */
+#if 0
+# define DEBUG_TRIEWALK
+#endif
+
+#define MAXWLEN 254		/* Assume max. word len is this many bytes.
+				   Some places assume a word length fits in a
+				   byte, thus it can't be above 255.
+				   Must be >= PFD_NOTSPECIAL. */
+
+/* Type used for indexes in the word tree need to be at least 4 bytes.  If int
+ * is 8 bytes we could use something smaller, but what? */
+#if VIM_SIZEOF_INT > 3
+typedef int idx_T;
+#else
+typedef long idx_T;
+#endif
+
+#ifdef FEAT_MBYTE
+typedef int salfirst_T;
+#else
+typedef short salfirst_T;
+#endif
+
+/*
+ * Structure used to store words and other info for one language, loaded from
+ * a .spl file.
+ * The main access is through the tree in "sl_fbyts/sl_fidxs", storing the
+ * case-folded words.  "sl_kbyts/sl_kidxs" is for keep-case words.
+ *
+ * The "byts" array stores the possible bytes in each tree node, preceded by
+ * the number of possible bytes, sorted on byte value:
+ *	<len> <byte1> <byte2> ...
+ * The "idxs" array stores the index of the child node corresponding to the
+ * byte in "byts".
+ * Exception: when the byte is zero, the word may end here and "idxs" holds
+ * the flags, region mask and affixID for the word.  There may be several
+ * zeros in sequence for alternative flag/region/affixID combinations.
+ */
+typedef struct slang_S slang_T;
+struct slang_S
+{
+    slang_T	*sl_next;	/* next language */
+    char_u	*sl_name;	/* language name "en", "en.rare", "nl", etc. */
+    char_u	*sl_fname;	/* name of .spl file */
+    int		sl_add;		/* TRUE if it's a .add file. */
+
+    char_u	*sl_fbyts;	/* case-folded word bytes */
+    idx_T	*sl_fidxs;	/* case-folded word indexes */
+    char_u	*sl_kbyts;	/* keep-case word bytes */
+    idx_T	*sl_kidxs;	/* keep-case word indexes */
+    char_u	*sl_pbyts;	/* prefix tree word bytes */
+    idx_T	*sl_pidxs;	/* prefix tree word indexes */
+
+    char_u	*sl_info;	/* infotext string or NULL */
+
+    char_u	sl_regions[17];	/* table with up to 8 region names plus NUL */
+
+    char_u	*sl_midword;	/* MIDWORD string or NULL */
+
+    hashtab_T	sl_wordcount;	/* hashtable with word count, wordcount_T */
+
+    int		sl_compmax;	/* COMPOUNDWORDMAX (default: MAXWLEN) */
+    int		sl_compminlen;	/* COMPOUNDMIN (default: 0) */
+    int		sl_compsylmax;	/* COMPOUNDSYLMAX (default: MAXWLEN) */
+    int		sl_compoptions;	/* COMP_* flags */
+    garray_T	sl_comppat;	/* CHECKCOMPOUNDPATTERN items */
+    regprog_T	*sl_compprog;	/* COMPOUNDRULE turned into a regexp progrm
+				 * (NULL when no compounding) */
+    char_u	*sl_comprules;	/* all COMPOUNDRULE concatenated (or NULL) */
+    char_u	*sl_compstartflags; /* flags for first compound word */
+    char_u	*sl_compallflags; /* all flags for compound words */
+    char_u	sl_nobreak;	/* When TRUE: no spaces between words */
+    char_u	*sl_syllable;	/* SYLLABLE repeatable chars or NULL */
+    garray_T	sl_syl_items;	/* syllable items */
+
+    int		sl_prefixcnt;	/* number of items in "sl_prefprog" */
+    regprog_T	**sl_prefprog;	/* table with regprogs for prefixes */
+
+    garray_T	sl_rep;		/* list of fromto_T entries from REP lines */
+    short	sl_rep_first[256];  /* indexes where byte first appears, -1 if
+				       there is none */
+    garray_T	sl_sal;		/* list of salitem_T entries from SAL lines */
+    salfirst_T	sl_sal_first[256];  /* indexes where byte first appears, -1 if
+				       there is none */
+    int		sl_followup;	/* SAL followup */
+    int		sl_collapse;	/* SAL collapse_result */
+    int		sl_rem_accents;	/* SAL remove_accents */
+    int		sl_sofo;	/* SOFOFROM and SOFOTO instead of SAL items:
+				 * "sl_sal_first" maps chars, when has_mbyte
+				 * "sl_sal" is a list of wide char lists. */
+    garray_T	sl_repsal;	/* list of fromto_T entries from REPSAL lines */
+    short	sl_repsal_first[256];  /* sl_rep_first for REPSAL lines */
+    int		sl_nosplitsugs;	/* don't suggest splitting a word */
+    int		sl_nocompoundsugs; /* don't suggest compounding */
+
+    /* Info from the .sug file.  Loaded on demand. */
+    time_t	sl_sugtime;	/* timestamp for .sug file */
+    char_u	*sl_sbyts;	/* soundfolded word bytes */
+    idx_T	*sl_sidxs;	/* soundfolded word indexes */
+    buf_T	*sl_sugbuf;	/* buffer with word number table */
+    int		sl_sugloaded;	/* TRUE when .sug file was loaded or failed to
+				   load */
+
+    int		sl_has_map;	/* TRUE if there is a MAP line */
+#ifdef FEAT_MBYTE
+    hashtab_T	sl_map_hash;	/* MAP for multi-byte chars */
+    int		sl_map_array[256]; /* MAP for first 256 chars */
+#else
+    char_u	sl_map_array[256]; /* MAP for first 256 chars */
+#endif
+    hashtab_T	sl_sounddone;	/* table with soundfolded words that have
+				   handled, see add_sound_suggest() */
+};
+
+#ifdef VMS
+# define SPL_FNAME_TMPL  "%s_%s.spl"
+# define SPL_FNAME_ADD   "_add."
+# define SPL_FNAME_ASCII "_ascii."
+#else
+# define SPL_FNAME_TMPL  "%s.%s.spl"
+# define SPL_FNAME_ADD   ".add."
+# define SPL_FNAME_ASCII ".ascii."
+#endif
+
+/* Flags used for a word.  Only the lowest byte can be used, the region byte
+ * comes above it. */
+#define WF_REGION   0x01	/* region byte follows */
+#define WF_ONECAP   0x02	/* word with one capital (or all capitals) */
+#define WF_ALLCAP   0x04	/* word must be all capitals */
+#define WF_RARE	    0x08	/* rare word */
+#define WF_BANNED   0x10	/* bad word */
+#define WF_AFX	    0x20	/* affix ID follows */
+#define WF_FIXCAP   0x40	/* keep-case word, allcap not allowed */
+#define WF_KEEPCAP  0x80	/* keep-case word */
+
+/* for <flags2>, shifted up one byte to be used in wn_flags */
+#define WF_HAS_AFF  0x0100	/* word includes affix */
+#define WF_NEEDCOMP 0x0200	/* word only valid in compound */
+#define WF_NOSUGGEST 0x0400	/* word not to be suggested */
+#define WF_COMPROOT 0x0800	/* already compounded word, COMPOUNDROOT */
+#define WF_NOCOMPBEF 0x1000	/* no compounding before this word */
+#define WF_NOCOMPAFT 0x2000	/* no compounding after this word */
+
+/* flags for <pflags> */
+#define WFP_RARE	    0x01	/* rare prefix */
+#define WFP_NC		    0x02	/* prefix is not combining */
+#define WFP_UP		    0x04	/* to-upper prefix */
+#define WFP_COMPPERMIT	    0x08	/* prefix with COMPOUNDPERMITFLAG */
+#define WFP_COMPFORBID	    0x10	/* prefix with COMPOUNDFORBIDFLAG */
+
+/* Flags for postponed prefixes in "sl_pidxs".  Must be above affixID (one
+ * byte) and prefcondnr (two bytes). */
+#define WF_RAREPFX  (WFP_RARE << 24)	/* rare postponed prefix */
+#define WF_PFX_NC   (WFP_NC << 24)	/* non-combining postponed prefix */
+#define WF_PFX_UP   (WFP_UP << 24)	/* to-upper postponed prefix */
+#define WF_PFX_COMPPERMIT (WFP_COMPPERMIT << 24) /* postponed prefix with
+						  * COMPOUNDPERMITFLAG */
+#define WF_PFX_COMPFORBID (WFP_COMPFORBID << 24) /* postponed prefix with
+						  * COMPOUNDFORBIDFLAG */
+
+/* flags for <compoptions> */
+#define COMP_CHECKDUP		1	/* CHECKCOMPOUNDDUP */
+#define COMP_CHECKREP		2	/* CHECKCOMPOUNDREP */
+#define COMP_CHECKCASE		4	/* CHECKCOMPOUNDCASE */
+#define COMP_CHECKTRIPLE	8	/* CHECKCOMPOUNDTRIPLE */
+
+/* Info from "REP", "REPSAL" and "SAL" entries in ".aff" file used in si_rep,
+ * si_repsal, sl_rep, and si_sal.  Not for sl_sal!
+ * One replacement: from "ft_from" to "ft_to". */
+typedef struct fromto_S
+{
+    char_u	*ft_from;
+    char_u	*ft_to;
+} fromto_T;
+
+/* Info from "SAL" entries in ".aff" file used in sl_sal.
+ * The info is split for quick processing by spell_soundfold().
+ * Note that "sm_oneof" and "sm_rules" point into sm_lead. */
+typedef struct salitem_S
+{
+    char_u	*sm_lead;	/* leading letters */
+    int		sm_leadlen;	/* length of "sm_lead" */
+    char_u	*sm_oneof;	/* letters from () or NULL */
+    char_u	*sm_rules;	/* rules like ^, $, priority */
+    char_u	*sm_to;		/* replacement. */
+#ifdef FEAT_MBYTE
+    int		*sm_lead_w;	/* wide character copy of "sm_lead" */
+    int		*sm_oneof_w;	/* wide character copy of "sm_oneof" */
+    int		*sm_to_w;	/* wide character copy of "sm_to" */
+#endif
+} salitem_T;
+
+/* Values for SP_*ERROR are negative, positive values are used by
+ * read_cnt_string(). */
+#define	SP_TRUNCERROR	-1	/* spell file truncated error */
+#define	SP_FORMERROR	-2	/* format error in spell file */
+#define SP_OTHERERROR	-3	/* other error while reading spell file */
+
+/*
+ * Structure used in "b_langp", filled from 'spelllang'.
+ */
+typedef struct langp_S
+{
+    slang_T	*lp_slang;	/* info for this language */
+    slang_T	*lp_sallang;	/* language used for sound folding or NULL */
+    slang_T	*lp_replang;	/* language used for REP items or NULL */
+    int		lp_region;	/* bitmask for region or REGION_ALL */
+} langp_T;
+
+#define LANGP_ENTRY(ga, i)	(((langp_T *)(ga).ga_data) + (i))
+
+#define VIMSUGMAGIC "VIMsug"	/* string at start of Vim .sug file */
+#define VIMSUGMAGICL 6
+#define VIMSUGVERSION 1
+
+/*
+ * The tables used for recognizing word characters according to spelling.
+ * These are only used for the first 256 characters of 'encoding'.
+ */
+typedef struct spelltab_S
+{
+    char_u  st_isw[256];	/* flags: is word char */
+    char_u  st_isu[256];	/* flags: is uppercase char */
+    char_u  st_fold[256];	/* chars: folded case */
+    char_u  st_upper[256];	/* chars: upper case */
+} spelltab_T;
+
+/*
+ * Use our own character-case definitions, because the current locale may
+ * differ from what the .spl file uses.
+ * These must not be called with negative number!
+ */
+#ifndef FEAT_MBYTE
+/* Non-multi-byte implementation. */
+# define SPELL_TOFOLD(c) ((c) < 256 ? (int)spelltab.st_fold[c] : (c))
+# define SPELL_TOUPPER(c) ((c) < 256 ? (int)spelltab.st_upper[c] : (c))
+# define SPELL_ISUPPER(c) ((c) < 256 ? spelltab.st_isu[c] : FALSE)
+#else
+# if defined(HAVE_WCHAR_H)
+#  include <wchar.h>	    /* for towupper() and towlower() */
+# endif
+/* Multi-byte implementation.  For Unicode we can call utf_*(), but don't do
+ * that for ASCII, because we don't want to use 'casemap' here.  Otherwise use
+ * the "w" library function for characters above 255 if available. */
+# ifdef HAVE_TOWLOWER
+#  define SPELL_TOFOLD(c) (enc_utf8 && (c) >= 128 ? utf_fold(c) \
+	    : (c) < 256 ? (int)spelltab.st_fold[c] : (int)towlower(c))
+# else
+#  define SPELL_TOFOLD(c) (enc_utf8 && (c) >= 128 ? utf_fold(c) \
+	    : (c) < 256 ? (int)spelltab.st_fold[c] : (c))
+# endif
+
+# ifdef HAVE_TOWUPPER
+#  define SPELL_TOUPPER(c) (enc_utf8 && (c) >= 128 ? utf_toupper(c) \
+	    : (c) < 256 ? (int)spelltab.st_upper[c] : (int)towupper(c))
+# else
+#  define SPELL_TOUPPER(c) (enc_utf8 && (c) >= 128 ? utf_toupper(c) \
+	    : (c) < 256 ? (int)spelltab.st_upper[c] : (c))
+# endif
+
+# ifdef HAVE_ISWUPPER
+#  define SPELL_ISUPPER(c) (enc_utf8 && (c) >= 128 ? utf_isupper(c) \
+	    : (c) < 256 ? spelltab.st_isu[c] : iswupper(c))
+# else
+#  define SPELL_ISUPPER(c) (enc_utf8 && (c) >= 128 ? utf_isupper(c) \
+	    : (c) < 256 ? spelltab.st_isu[c] : (FALSE))
+# endif
+#endif
+
+#ifdef FEAT_SPELL
+/* First language that is loaded, start of the linked list of loaded
+ * languages. */
+# ifdef IN_SPELL_C
+#  define SPELL_EXTERN
+#  define SPELL_INIT(x) x
+# else
+#  define SPELL_EXTERN extern
+#  define SPELL_INIT(x)
+# endif
+
+SPELL_EXTERN slang_T	*first_lang SPELL_INIT(= NULL);
+
+/* file used for "zG" and "zW" */
+SPELL_EXTERN char_u	*int_wordlist SPELL_INIT(= NULL);
+
+
+SPELL_EXTERN char e_format[] SPELL_INIT(= N_("E759: Format error in spell file"));
+
+SPELL_EXTERN spelltab_T   spelltab;
+SPELL_EXTERN int	  did_set_spelltab;
+
+#endif