diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5625311
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/phonetic-letters
diff --git a/README.asciidoc b/README.asciidoc
new file mode 100644
index 0000000..f39ab27
--- /dev/null
+++ b/README.asciidoc
@@ -0,0 +1,80 @@
+= phonetic-letters
+
+This is a simple application which reveals the code word(s) from the NATO phonetic alphabet for a given set of letters from the English alphabet.
+
+This app can be used to help you memorize the NATO phonetic alphabet.
+
+== Installation
+
+=== Requirements
+
+==== Go
+
+A minimum version of Go 1.21.0 is required for installing spruce.
+Please go https://go.dev/dl/[here] to download the latest version.
+
+=== Install with Go
+
+[source,console]
+----
+git clone https://codeflow.dananglin.me.uk/apollo/phonetic-letters.git
+cd phonetic-letters
+go install .
+----
+
+== Usage
+
+Reveal the code word for `g`:
+[source,console]
+----
+$ phonetic-letters g
+G - Golf
+----
+
+Reveal the code words for all the letters in `Hello, World!`:
+[source,console]
+----
+$ phonetic-letters Hello, World!
+H - Hotel
+E - Echo
+L - Lima
+L - Lima
+O - Oscar
+W - Whiskey
+O - Oscar
+R - Romeo
+L - Lima
+D - Delta
+----
+
+Reveal the code words for all letters of the alphabet:
+[source,console]
+----
+$ ./phonetic-letters --all
+A - Alpha
+B - Bravo
+C - Charlie
+D - Delta
+E - Echo
+F - Foxtrot
+G - Golf
+H - Hotel
+I - India
+J - Juliet
+K - Kilo
+L - Lima
+M - Mike
+N - November
+O - Oscar
+P - Papa
+Q - Quebec
+R - Romeo
+S - Sierra
+T - Tango
+U - Uniform
+V - Victor
+W - Whiskey
+X - Xray
+Y - Yankee
+Z - Zulu
+----
diff --git a/README.md b/README.md
deleted file mode 100644
index 37f4f8d..0000000
--- a/README.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# phonetic-letters
-
-Reveals the code words from the NATO phonetic alphabet for a given set of letters from the alphabet.
\ No newline at end of file
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..a0463ed
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module codeflow.dananglin.me.uk/apollo/phonetic-letters
+
+go 1.21
diff --git a/phonetic_letters.go b/phonetic_letters.go
new file mode 100644
index 0000000..d5d3cd3
--- /dev/null
+++ b/phonetic_letters.go
@@ -0,0 +1,104 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func main() {
+	var all bool
+
+	flag.BoolVar(&all, "all", false, "reveal the code words of all the letters in the English alphabet.")
+	flag.Parse()
+
+	if all {
+		fmt.Println(phoneticLetters(fullAlphabet()))
+		return
+	}
+
+	args := flag.Args()
+
+	if len(args) < 1 {
+		fmt.Println("ERROR: expected an argument")
+		os.Exit(1)
+	} else if len(args) == 1 {
+		fmt.Println(phoneticLetters(args[0]))
+	} else {
+		input := ""
+		for i := range args {
+			input = input + args[i]
+		}
+		fmt.Println(phoneticLetters(input))
+	}
+}
+
+func phoneticLetters(letters string) string {
+	letters = strings.ToLower(letters)
+
+	b := strings.Builder{}
+
+	for _, r := range letters {
+		switch r {
+		case 'a':
+			b.WriteString("A - Alpha\n")
+		case 'b':
+			b.WriteString("B - Bravo\n")
+		case 'c':
+			b.WriteString("C - Charlie\n")
+		case 'd':
+			b.WriteString("D - Delta\n")
+		case 'e':
+			b.WriteString("E - Echo\n")
+		case 'f':
+			b.WriteString("F - Foxtrot\n")
+		case 'g':
+			b.WriteString("G - Golf\n")
+		case 'h':
+			b.WriteString("H - Hotel\n")
+		case 'i':
+			b.WriteString("I - India\n")
+		case 'j':
+			b.WriteString("J - Juliet\n")
+		case 'k':
+			b.WriteString("K - Kilo\n")
+		case 'l':
+			b.WriteString("L - Lima\n")
+		case 'm':
+			b.WriteString("M - Mike\n")
+		case 'n':
+			b.WriteString("N - November\n")
+		case 'o':
+			b.WriteString("O - Oscar\n")
+		case 'p':
+			b.WriteString("P - Papa\n")
+		case 'q':
+			b.WriteString("Q - Quebec\n")
+		case 'r':
+			b.WriteString("R - Romeo\n")
+		case 's':
+			b.WriteString("S - Sierra\n")
+		case 't':
+			b.WriteString("T - Tango\n")
+		case 'u':
+			b.WriteString("U - Uniform\n")
+		case 'v':
+			b.WriteString("V - Victor\n")
+		case 'w':
+			b.WriteString("W - Whiskey\n")
+		case 'x':
+			b.WriteString("X - Xray\n")
+		case 'y':
+			b.WriteString("Y - Yankee\n")
+		case 'z':
+			b.WriteString("Z - Zulu\n")
+		}
+	}
+
+	return b.String()
+}
+
+func fullAlphabet() string {
+	return "a b c d e f g h i j k l m n o p q r s t u v w x y z"
+}