diff --git a/Cargo.lock b/Cargo.lock
index 8856495..d13e961 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -271,7 +271,7 @@ name = "heck"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "unicode-segmentation 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -811,6 +811,7 @@ dependencies = [
  "serde_json 1.0.36 (registry+https://github.com/rust-lang/crates.io-index)",
  "structopt 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicase 1.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -828,7 +829,7 @@ dependencies = [
 
 [[package]]
 name = "unicode-segmentation"
-version = "1.2.1"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1013,7 +1014,7 @@ dependencies = [
 "checksum treeline 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a7f741b240f1a48843f9b8e0444fb55fb2a4ff67293b50a9179dfd5ea67f8d41"
 "checksum ucd-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "535c204ee4d8434478593480b8f86ab45ec9aae0e83c568ca81abf0fd0e88f86"
 "checksum unicase 1.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7f4765f83163b74f957c797ad9253caf97f103fb064d3999aea9568d09fc8a33"
-"checksum unicode-segmentation 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "aa6024fc12ddfd1c6dbc14a80fa2324d4568849869b779f6bd37e5e4c03344d1"
+"checksum unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1967f4cdfc355b37fd76d2a954fb2ed3871034eb4f26d60537d88795cfc332a9"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 "checksum unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
diff --git a/Cargo.toml b/Cargo.toml
index daef3c6..921ec74 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -36,6 +36,7 @@ unicase = "1.1"
 bstr = "0.2"
 log = "0.4"
 env_logger = "0.6"
+unicode-segmentation = "1.3.0"
 
 [dev-dependencies]
 assert_fs = "0.10"
diff --git a/src/tokens.rs b/src/tokens.rs
index d2fec14..421c59c 100644
--- a/src/tokens.rs
+++ b/src/tokens.rs
@@ -10,6 +10,7 @@ pub enum Case {
 pub struct ParserBuilder {
     ignore_hex: bool,
     include_digits: bool,
+    include_chars: String,
 }
 
 impl ParserBuilder {
@@ -27,11 +28,22 @@ impl ParserBuilder {
         self
     }
 
+    pub fn include_chars(&mut self, chars: String) -> &mut Self {
+        self.include_chars = chars;
+        self
+    }
+
     pub fn build(&self) -> Parser {
-        let mut pattern = r#"\b(\p{Alphabetic}|_|'"#.to_owned();
+        let mut pattern = r#"\b(\p{Alphabetic}"#.to_owned();
         if self.include_digits {
             pattern.push_str(r#"|\d"#);
         }
+        for grapheme in
+            unicode_segmentation::UnicodeSegmentation::graphemes(self.include_chars.as_str(), true)
+        {
+            let escaped = regex::escape(&grapheme);
+            pattern.push_str(&format!("|{}", escaped));
+        }
         pattern.push_str(r#")+\b"#);
         let words_str = regex::Regex::new(&pattern).unwrap();
         let words_bytes = regex::bytes::Regex::new(&pattern).unwrap();
@@ -48,6 +60,7 @@ impl Default for ParserBuilder {
         Self {
             ignore_hex: true,
             include_digits: true,
+            include_chars: "_'".to_owned(),
         }
     }
 }