diff --git a/Tools/langtool/.gitignore b/Tools/langtool/.gitignore
new file mode 100644
index 0000000000..eb5a316cbd
--- /dev/null
+++ b/Tools/langtool/.gitignore
@@ -0,0 +1 @@
+target
diff --git a/Tools/langtool/Cargo.lock b/Tools/langtool/Cargo.lock
new file mode 100644
index 0000000000..5c4ab6d00b
--- /dev/null
+++ b/Tools/langtool/Cargo.lock
@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "langtool"
+version = "0.1.0"
diff --git a/Tools/langtool/Cargo.toml b/Tools/langtool/Cargo.toml
new file mode 100644
index 0000000000..ad24cc8bb0
--- /dev/null
+++ b/Tools/langtool/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "langtool"
+version = "0.1.0"
+authors = ["Henrik Rydgård <hrydgard@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/Tools/langtool/README.md b/Tools/langtool/README.md
new file mode 100644
index 0000000000..667472552a
--- /dev/null
+++ b/Tools/langtool/README.md
@@ -0,0 +1,17 @@
+# Language ini file processor tool
+
+Wrote it quickly in rust as a little exercise.
+
+To run, with rust installed:
+
+```rust
+cargo run
+```
+
+To autoformat the code, use:
+
+```rust
+cargo fmt
+```
+
+or set up your IDE to do that.
diff --git a/Tools/langtool/src/main.rs b/Tools/langtool/src/main.rs
new file mode 100644
index 0000000000..f17b2c227d
--- /dev/null
+++ b/Tools/langtool/src/main.rs
@@ -0,0 +1,230 @@
+use std::fs::File;
+use std::io::{self, BufRead, Write};
+use std::path::{Path, PathBuf};
+
+// Super simplified ini file processor.
+// Doesn't even bother with understanding comments.
+// Just understands section headings and
+// keys and values, split by ' = '.
+
+#[derive(Debug, Clone)]
+struct Section {
+    name: String,
+    title_line: String,
+    lines: Vec<String>,
+}
+
+impl Section {
+    fn insert_line_if_missing(&mut self, line: &str) -> bool {
+        let prefix = if let Some(pos) = line.find(" =") {
+            &line[0..pos + 2]
+        } else {
+            return false;
+        };
+        let prefix = prefix.to_owned();
+
+        for iter_line in &self.lines {
+            if iter_line.starts_with(&prefix) {
+                // Already have it
+                return false;
+            }
+        }
+
+        // Now try to insert it at an alphabetic-ish location.
+
+        // Then, find a suitable insertion spot
+        for (i, iter_line) in self.lines.iter().enumerate() {
+            if iter_line > &prefix {
+                println!("Inserting line {} into {}", line, self.name);
+                self.lines.insert(i, line.to_owned());
+                return true;
+            }
+        }
+        println!("failed to insert {}", line);
+        return true;
+    }
+}
+
+#[derive(Debug)]
+struct IniFile {
+    filename: PathBuf,
+    preamble: Vec<String>,
+    sections: Vec<Section>,
+    has_bom: bool,
+}
+
+impl IniFile {
+    fn parse(filename: &str) -> io::Result<IniFile> {
+        let lines = read_lines(filename)?;
+
+        let mut sections = vec![];
+        let mut preamble = vec![];
+        let mut cur_section = None;
+
+        let mut has_bom = false;
+
+        for line in lines {
+            let line = line.unwrap();
+
+            let line = if line.starts_with("\u{feff}") {
+                has_bom = true;
+                &line[3..]
+            } else {
+                &line
+            };
+
+            if let Some('[') = line.chars().next() {
+                if let Some(right_bracket) = line.find(']') {
+                    if let Some(section) = cur_section.take() {
+                        sections.push(section);
+                    }
+
+                    let name = &line[1..right_bracket];
+                    cur_section = Some(Section {
+                        name: name.to_owned(),
+                        title_line: line.to_owned(), // preserves comment and bom
+                        lines: vec![],
+                    });
+                } else {
+                    // Bad syntax
+                    break;
+                }
+            } else {
+                if let Some(cur_section) = &mut cur_section {
+                    cur_section.lines.push(line.to_owned());
+                } else {
+                    preamble.push(line.to_owned());
+                }
+            }
+        }
+
+        if let Some(section) = cur_section.take() {
+            sections.push(section);
+        }
+
+        let ini = IniFile {
+            filename: PathBuf::from(filename),
+            preamble,
+            sections,
+            has_bom,
+        };
+        Ok(ini)
+    }
+
+    fn write(&self) -> io::Result<()> {
+        let file = std::fs::File::create(&self.filename)?;
+        let mut file = std::io::LineWriter::new(file);
+
+        // Write BOM
+        if self.has_bom {
+            file.write_all("\u{feff}".as_bytes())?;
+        }
+        for line in &self.preamble {
+            file.write_all(line.as_bytes())?;
+            file.write(b"\n")?;
+        }
+        for section in &self.sections {
+            file.write_all(section.title_line.as_bytes())?;
+            file.write(b"\n")?;
+            for line in &section.lines {
+                file.write_all(line.as_bytes())?;
+                file.write(b"\n")?;
+            }
+        }
+
+        Ok(())
+    }
+
+    // Assumes alphabetical section order!
+    fn insert_section_if_missing(&mut self, section: &Section) -> bool {
+        // First, check if it's there.
+
+        for iter_section in &self.sections {
+            if iter_section.name == section.name {
+                return false;
+            }
+        }
+
+        // Then, find a suitable insertion spot
+        for (i, iter_section) in self.sections.iter_mut().enumerate() {
+            if iter_section.name > section.name {
+                println!("Inserting section {}", section.name);
+                self.sections.insert(i, section.clone());
+                return true;
+            }
+        }
+        // Reached the end for some reason? Add it.
+        self.sections.push(section.clone());
+        return true;
+    }
+
+    fn get_section_mut(&mut self, section_name: &str) -> Option<&mut Section> {
+        for section in &mut self.sections {
+            if section.name == section_name {
+                return Some(section);
+            }
+        }
+        None
+    }
+}
+
+// Grabbed from a sample, a fast line reader iterator.
+fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
+where
+    P: AsRef<Path>,
+{
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file).lines())
+}
+
+fn copy_missing_lines(reference_ini: &IniFile, target_ini: &mut IniFile) {
+    // Insert any missing full sections.
+    for section in &reference_ini.sections {
+        if !target_ini.insert_section_if_missing(section) {
+            if let Some(target_section) = target_ini.get_section_mut(&section.name) {
+                for line in &section.lines {
+                    target_section.insert_line_if_missing(line);
+                }
+            }
+        }
+    }
+
+    target_ini.write();
+}
+
+fn main() {
+    let args: Vec<_> = std::env::args().skip(1).collect();
+
+    let mut filenames = args;
+
+    println!("{:?}", filenames);
+
+    let root = "../../assets/lang";
+    let reference_file = "en_US.ini";
+
+    let reference_ini = IniFile::parse(&format!("{}/{}", root, reference_file)).unwrap();
+
+    if filenames.is_empty() {
+        // Grab them all.
+        for path in std::fs::read_dir(root).unwrap() {
+            let path = path.unwrap();
+            if path.file_name() == reference_file {
+                continue;
+            }
+            filenames.push(path.file_name().to_string_lossy().to_string());
+        }
+    }
+
+    for filename in filenames {
+        if filename == "langtool" || !filename.ends_with("ini") {
+            // Get this from cargo run for some reason.
+            continue;
+        }
+        let target_ini_filename = format!("{}/{}", root, filename);
+        println!("Langtool processing {}", target_ini_filename);
+        let mut target_ini = IniFile::parse(&target_ini_filename).unwrap();
+        copy_missing_lines(&reference_ini, &mut target_ini);
+    }
+
+    // println!("{:#?}", target_ini);
+}
diff --git a/assets/lang/ja_JP.ini b/assets/lang/ja_JP.ini
index e249370b5c..d28cfcccaa 100644
--- a/assets/lang/ja_JP.ini
+++ b/assets/lang/ja_JP.ini
@@ -38,7 +38,6 @@ Combo Key Setting = コンボキーの設定
 Combo Key Setup = コンボキーを設定する
 Confine Mouse = ウィンドウ/表示領域内でマウスをトラップする
 Control Mapping = キーを設定する
-Customize Touch Controls = カスタムレイアウト...
 Customize tilt = 傾きをカスタマイズする
 Customize Touch Controls = 画面タッチ用コントローラーをカスタマイズする
 D-PAD = 方向キー