diff --git a/languages_substitution.go b/languages_substitution.go
index d6664e2..a1932be 100644
--- a/languages_substitution.go
+++ b/languages_substitution.go
@@ -16,14 +16,15 @@ func init() {
 	}
 }
 
+// BUG: Initialized on init so also impossible to set custom separator.
 var defaultSub = map[rune]string{
 	'"':  "",
 	'\'': "",
 	'’':  "",
-	'‒':  "-", // figure dash
-	'–':  "-", // en dash
-	'—':  "-", // em dash
-	'―':  "-", // horizontal bar
+	'‒':  string(Separator), // figure dash
+	'–':  string(Separator), // en dash
+	'—':  string(Separator), // em dash
+	'―':  string(Separator), // horizontal bar
 }
 
 var deSub = map[rune]string{
diff --git a/slug.go b/slug.go
index 0c6801f..92a40e6 100644
--- a/slug.go
+++ b/slug.go
@@ -28,8 +28,13 @@ var (
 	// after MaxLength.
 	MaxLength int
 
-	regexpNonAuthorizedChars = regexp.MustCompile("[^a-z0-9-_]")
-	regexpMultipleDashes     = regexp.MustCompile("-+")
+	// Separator configure default separator for all slugs.
+	// By default set to '-'.
+	Separator = '-'
+
+	// BUG: Not possible to change separator from default.
+	regexpNonAuthorizedChars = regexp.MustCompile("[^a-z0-9-_" + string(Separator) + "]")
+	regexpMultipleSeparators = regexp.MustCompile(string(Separator) + "+")
 )
 
 //=============================================================================
@@ -76,14 +81,15 @@ func MakeLang(s string, lang string) (slug string) {
 	slug = strings.ToLower(slug)
 
 	// Process all remaining symbols
-	slug = regexpNonAuthorizedChars.ReplaceAllString(slug, "-")
-	slug = regexpMultipleDashes.ReplaceAllString(slug, "-")
-	slug = strings.Trim(slug, "-_")
+	slug = regexpNonAuthorizedChars.ReplaceAllString(slug, string(Separator))
+	slug = regexpMultipleSeparators.ReplaceAllString(slug, string(Separator))
 
 	if MaxLength > 0 {
 		slug = smartTruncate(slug)
 	}
 
+	slug = strings.Trim(slug, "-_"+string(Separator))
+
 	return slug
 }
 
@@ -137,7 +143,7 @@ func smartTruncate(text string) string {
 			break
 		}
 	}
-	return strings.Trim(truncated, "-")
+	return truncated
 }
 
 // IsSlug returns True if provided text does not contain white characters,
@@ -148,12 +154,15 @@ func smartTruncate(text string) string {
 func IsSlug(text string) bool {
 	if text == "" ||
 		(MaxLength > 0 && len(text) > MaxLength) ||
-		text[0] == '-' || text[0] == '_' ||
-		text[len(text)-1] == '-' || text[len(text)-1] == '_' {
+		strings.HasPrefix(text, "-") || strings.HasPrefix(text, "_") ||
+		strings.HasPrefix(text, string(Separator)) ||
+		strings.HasSuffix(text, "-") || strings.HasSuffix(text, "_") ||
+		strings.HasSuffix(text, string(Separator)) {
 		return false
 	}
 	for _, c := range text {
-		if (c < 'a' || c > 'z') && c != '-' && c != '_' && (c < '0' || c > '9') {
+		if (c < 'a' || c > 'z') && (c < '0' || c > '9') &&
+			c != '-' && c != '_' && c != Separator {
 			return false
 		}
 	}
diff --git a/slug_test.go b/slug_test.go
index a6795f8..2ebf4c4 100644
--- a/slug_test.go
+++ b/slug_test.go
@@ -208,6 +208,7 @@ func TestSlugMakeSmartTruncate(t *testing.T) {
 		{"DOBROSLAWZYBORT", 100, "dobroslawzybort"},
 		{"Dobroslaw Zybort", 100, "dobroslaw-zybort"},
 		{"Dobroslaw Zybort", 12, "dobroslaw"},
+		{"Dobroslaw-Zybort_-_-", 11, "dobroslaw"},
 		{"  Dobroslaw     Zybort  ?", 12, "dobroslaw"},
 		{"Ala ma 6 kotów.", 10, "ala-ma-6"},
 		{"Dobrosław Żybort", 5, "dobro"},
@@ -266,6 +267,95 @@ func TestIsSlug(t *testing.T) {
 	})
 }
 
+func TestSeparatorSlug(t *testing.T) {
+	MaxLength = 0
+	type args struct {
+		separator rune
+		text      string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{"separator -", args{'-', "test---slug"}, "test-slug"},
+		{"separator _", args{'_', "test___slug"}, "test_slug"},
+		{"separator /", args{'/', "test///slug"}, "test/slug"},
+		{"separator ☺", args{'☺', "test slug"}, "test☺slug"},
+		{"remove ASCII first", args{'☺', "test☺☺slug ☺"}, "testslug"},
+	}
+	for _, tt := range tests {
+		Separator = tt.args.separator
+
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Make(tt.args.text); got != tt.want {
+				t.Errorf("Make() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+	// Global state...
+	Separator = '-'
+}
+
+func TestSeparatorSlugMakeLang(t *testing.T) {
+	var testCases = []struct {
+		separator rune
+		lang      string
+		in        string
+		want      string
+	}{
+		// & fun.
+		{'_', "de", "This & that", "this_und_that"},
+		{'_', "en", "This & that", "this_and_that"},
+		{'_', "test", "This & that", "this_and_that"}, // unknown lang, fallback to "en"
+		// Test defaultSub.
+		{'_', "de", "1\"2'3’4‒5–6—7―8", "1234_5_6_7_8"},
+		{'_', "en", "1\"2'3’4‒5–6—7―8", "1234_5_6_7_8"},
+	}
+
+	for index, smlt := range testCases {
+		Separator = smlt.separator
+		got := MakeLang(smlt.in, smlt.lang)
+		if got != smlt.want {
+			t.Errorf(
+				"%d. MakeLang(%#v, %#v) = %#v; want %#v",
+				index, smlt.in, smlt.lang, got, smlt.want)
+		}
+	}
+	// Global state...
+	Separator = '-'
+}
+
+func TestSeparatorIsSlug(t *testing.T) {
+	MaxLength = 0
+	type args struct {
+		separator rune
+		text      string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{"separator -", args{'-', "test slug"}, true},
+		{"separator _", args{'_', "test slug"}, true},
+		{"separator /", args{'/', "test slug"}, true},
+		{"separator ☺", args{'☺', "test slug"}, true},
+	}
+	for _, tt := range tests {
+		Separator = tt.args.separator
+
+		t.Run(tt.name, func(t *testing.T) {
+			slug := Make(tt.args.text)
+			if got := IsSlug(slug); got != tt.want {
+				t.Errorf("IsSlug('%s') = %v, want %v", slug, got, tt.want)
+			}
+		})
+	}
+	// Global state...
+	Separator = '-'
+}
+
 func BenchmarkMakeShortAscii(b *testing.B) {
 	b.ReportAllocs()
 	for n := 0; n < b.N; n++ {