diff --git a/lib/lang/gd.js b/lib/lang/gd.js
new file mode 100644
index 00000000..4c2b0bc5
--- /dev/null
+++ b/lib/lang/gd.js
@@ -0,0 +1,147 @@
+"use strict";
+
+function join_with_shared_prefix(a, b, joiner) {
+  let i = 0;
+
+  while(i !== a.length &&
+        i !== b.length &&
+        a.charCodeAt(i) === b.charCodeAt(i))
+    ++i;
+
+  while(i && a.charCodeAt(i - 1) !== 32)
+    --i;
+
+  return a + joiner + b.slice(i);
+}
+
+module.exports = {
+  "clear": "soilleir",
+  "no-precipitation": "gun sileadh",
+  "mixed-precipitation": "sileadh measgaichte",
+  "possible-very-light-precipitation": "tha cothrom ann gum bi sileadh glè aotrom ann",
+  "very-light-precipitation": "sileadh glè aotrom",
+  "possible-light-precipitation": "tha cothrom ann gum bi sileadh aotrom ann",
+  "light-precipitation": "sileadh aotrom",
+  "medium-precipitation": "sileadh",
+  "heavy-precipitation": "sileadh trom",
+  "possible-very-light-rain": "tha cothrom ann gum bi uisge glè aotrom ann",
+  "very-light-rain": "uisge glè aotrom",
+  "possible-light-rain": "tha cothrom ann gum bi uisge aotrom ann",
+  "light-rain": "uisge aotrom",
+  "medium-rain": "uisge",
+  "heavy-rain": "uisge trom",
+  "possible-very-light-sleet": "tha cothrom ann gum bi flin glè aotrom ann",
+  "very-light-sleet": "flin glè aotrom",
+  "possible-light-sleet": "tha cothrom ann gum bi flin aotrom ann",
+  "light-sleet": "flin aotrom",
+  "medium-sleet": "flin",
+  "heavy-sleet": "flin trom",
+  "possible-very-light-snow": "tha cothrom ann gum bi fras sneachda ann",
+  "very-light-snow": "frasan sneachda",
+  "possible-light-snow": "tha cothrom ann gum bi sneachd aotrom ann",
+  "light-snow": "sneachd aotrom",
+  "medium-snow": "sneachd",
+  "heavy-snow": "sneachda trom",
+  "possible-thunderstorm": "tha cothrom ann gum bi stoirmean tàirneanaich ann",
+  "thunderstorm": "stoirmean tàirneanaich",
+  "light-wind": "oiteag shocair",
+  "medium-wind": "gaoth",
+  "heavy-wind": "gaoth chunnartach",
+  "low-humidity": "tioram",
+  "high-humidity": "tais",
+  "fog": "ceòthach",
+  "light-clouds": "sgothan aotrom",
+  "medium-clouds": "sgothach",
+  "heavy-clouds": "sgothan trom",
+  "today-morning": "madainn an-diugh",
+  "later-today-morning": "nas anmoiche madainn an-diugh",
+  "today-afternoon": "feasgar an-diugh",
+  "later-today-afternoon": "nas anmoiche feasgar an-diugh",
+  "today-evening": "feasgar an-diugh",
+  "later-today-evening": "nas anmoiche feasgar an-diugh",
+  "today-night": "a-nochd",
+  "later-today-night": "nas anmoiche a-nochd",
+  "tomorrow-morning": "madainn a-màireach",
+  "tomorrow-afternoon": "feasgar a-màireach",
+  "tomorrow-evening": "feasgar a-màireach",
+  "tomorrow-night": "an ath oidhche",
+  "morning": "anns a' mhadainn",
+  "afternoon": "anns an fheasgar",
+  "evening": "anns an fheasgar",
+  "night": "a-nochd",
+  "today": "an-diugh",
+  "tomorrow": "a-màireach",
+  "sunday": "Didòmhnaich",
+  "monday": "Diluain",
+  "tuesday": "Dimàirt",
+  "wednesday": "Diciadain",
+  "thursday": "Diardaoin",
+  "friday": "Dihaoine",
+  "saturday": "Disathairne",
+  "next-sunday": "Didòmhnaich an ath sheachdain",
+  "next-monday": "Diluain an ath sheachdain",
+  "next-tuesday": "Dimàirt an ath sheachdain",
+  "next-wednesday": "Diciadain an ath sheachdain",
+  "next-thursday": "Diardaoin an ath sheachdain",
+  "next-friday": "Dihaoine an ath sheachdain",
+  "next-saturday": "Disathairne an ath sheachdain",
+  "minutes": "$1 mion.",
+  "fahrenheit": "$1\u00B0F",
+  "celsius": "$1\u00B0C",
+  "inches": "$1 òir.",
+  "centimeters": "$1 cm.",
+  "less-than": "< $1",
+  "and": function(a, b) {
+    return join_with_shared_prefix(
+      a,
+      b,
+      a.indexOf(",") !== -1 ? ", agus " : " agus "
+    );
+  },
+  "through": function(a, b) {
+    return join_with_shared_prefix(a, b, " tro ");
+  },
+  "with": "$1, le $2",
+  "range": "$1\u2013$2",
+  "parenthetical": "$1 ($2)",
+  "for-hour": "$1 fad uair a thìde",
+  "starting-in": "$1 a' tòiseachadh ann an $2",
+  "stopping-in": "$1 a' stad ann an $2",
+  "starting-then-stopping-later": "$1 a' tòiseachadh ann an $2, a' stad as dèidh $3",
+  "stopping-then-starting-later": "$1 a' stad ann an $2, a' tòiseachadh a-rithist as dèidh $3",
+  "for-day": "$1 fad an latha",
+  "starting": "$1 a' tòiseachadh $2",
+  "until": "$1 a' stad $2",
+  "until-starting-again": "$1 a' stad $2, a' tòiseachadh a-rithist $3",
+  "starting-continuing-until": "$1 a' tòiseachadh $2, a' stad $3",
+  "during": "$1 $2",
+  "for-week": "$1 fad na seachdain",
+  "over-weekend": "$1 thairis air an deireadh-sheachdain",
+  "temperatures-peaking": "an teòthachd as àirde a' ruigsinn $1 $2",
+  "temperatures-rising": "an teòthachd as àirde a' ruigsinn $1 $2",
+  "temperatures-valleying": "an teòthachd as àirde a' tuiteam gu $1 $2",
+  "temperatures-falling": "an teòthachd as àirde a' tuiteam gu $1 $2",
+  // Capitalize the first letter of every word, except if that word is
+  // "and". (This is a very crude bastardization of proper English titling
+  // rules, but it is adequate for the purposes of this module.)
+  "title": function(str) {
+    return str.replace(/\S+/g, function(word) {
+      return word === "Agus" ?
+        word :
+        word.charAt(0).toUpperCase() + word.slice(1);
+    });
+  },
+  /* Capitalize the first word of the sentence and end with a period. */
+  "sentence": function(str) {
+    /* Capitalize. */
+    str = str.charAt(0).toUpperCase() + str.slice(1);
+
+    /* Add a period if there isn't already one. */
+    if(str.charAt(str.length - 1) !== ".")
+      str += ".";
+
+    return str;
+  },
+  "unavailable-radar": "Cha deach dad a lorg an-dràsta air sgàth 's $1.",
+  "station-offline": "gu bheil a h-uile stèisean-radar far loidhne",
+};
diff --git a/test_cases/gd.json b/test_cases/gd.json
new file mode 100644
index 00000000..e3cd216e
--- /dev/null
+++ b/test_cases/gd.json
@@ -0,0 +1,246 @@
+{
+  "Soilleir":
+    ["title", "clear"],
+
+  "Tha Cothrom Ann Gum Bi Sileadh Glè Aotrom Ann":
+    ["title", "possible-very-light-precipitation"],
+
+  "Sileadh Glè Aotrom":
+    ["title", "very-light-precipitation"],
+
+  "Tha Cothrom Ann Gum Bi Sileadh Aotrom Ann":
+    ["title", "possible-light-precipitation"],
+
+  "Sileadh Aotrom":
+    ["title", "light-precipitation"],
+
+  "Sileadh":
+    ["title", "medium-precipitation"],
+
+  "Sileadh Trom":
+    ["title", "heavy-precipitation"],
+
+  "Tha Cothrom Ann Gum Bi Uisge Glè Aotrom Ann":
+    ["title", "possible-very-light-rain"],
+
+  "Uisge Glè Aotrom":
+    ["title", "very-light-rain"],
+
+  "Tha Cothrom Ann Gum Bi Uisge Aotrom Ann":
+    ["title", "possible-light-rain"],
+
+  "Uisge Aotrom":
+    ["title", "light-rain"],
+
+  "Uisge":
+    ["title", "medium-rain"],
+
+  "Uisge Trom":
+    ["title", "heavy-rain"],
+
+  "Tha Cothrom Ann Gum Bi Flin Glè Aotrom Ann":
+    ["title", "possible-very-light-sleet"],
+
+  "Flin Glè Aotrom":
+    ["title", "very-light-sleet"],
+
+  "Tha Cothrom Ann Gum Bi Flin Aotrom Ann":
+    ["title", "possible-light-sleet"],
+
+  "Flin Aotrom":
+    ["title", "light-sleet"],
+
+  "Flin":
+    ["title", "medium-sleet"],
+
+  "Flin Trom":
+    ["title", "heavy-sleet"],
+
+  "Tha Cothrom Ann Gum Bi Fras Sneachda Ann":
+    ["title", "possible-very-light-snow"],
+
+  "Frasan Sneachda":
+    ["title", "very-light-snow"],
+
+  "Tha Cothrom Ann Gum Bi Sneachd Aotrom Ann":
+    ["title", "possible-light-snow"],
+
+  "Sneachd Aotrom":
+    ["title", "light-snow"],
+
+  "Sneachd":
+    ["title", "medium-snow"],
+
+  "Sneachda Trom":
+    ["title", "heavy-snow"],
+
+  "Gaoth":
+    ["title", "medium-wind"],
+
+  "Gaoth Chunnartach":
+    ["title", "heavy-wind"],
+
+  "Ceòthach":
+    ["title", "fog"],
+
+  "Sgothach":
+    ["title", "medium-clouds"],
+
+  "Sgothan Trom":
+    ["title", "heavy-clouds"],
+
+  "Tioram Agus Oiteag Shocair":
+    ["title", ["and", "low-humidity", "light-wind"]],
+
+  "Uisge Glè Aotrom Agus Gaoth Chunnartach":
+    ["title", ["and", "very-light-rain", "heavy-wind"]],
+
+  "Tais Agus Sgothan Aotrom":
+    ["title", ["and", "high-humidity", "light-clouds"]],
+
+
+  "Soilleir fad uair a thìde.":
+    ["sentence", ["for-hour", "clear"]],
+
+  "Frasan sneachda a' tòiseachadh ann an 35 mion.":
+    ["sentence", ["starting-in", "very-light-snow", ["minutes", 35]]],
+
+  "Uisge aotrom a' stad ann an 15 mion.":
+    ["sentence", ["stopping-in", "light-rain", ["minutes", 15]]],
+
+  "Flin trom a' tòiseachadh ann an 20 mion., a' stad as dèidh 30 mion.":
+    ["sentence",
+      ["starting-then-stopping-later",
+        "heavy-sleet",
+        ["minutes", 20],
+        ["minutes", 30]]],
+
+  "Uisge a' stad ann an 25 mion., a' tòiseachadh a-rithist as dèidh 8 mion.":
+    ["sentence",
+      ["stopping-then-starting-later",
+        "medium-rain",
+        ["minutes", 25],
+        ["minutes", 8]]],
+
+
+  "Sgothach fad an latha.":
+    ["sentence", ["for-day", "medium-clouds"]],
+
+  "Flin glè aotrom a' tòiseachadh anns a' mhadainn.":
+    ["sentence", ["starting", "very-light-sleet", "morning"]],
+
+  "Gaoth a' stad a-nochd.":
+    ["sentence", ["until", "medium-wind", "today-night"]],
+
+  "Sileadh trom a' stad anns an fheasgar.":
+    ["sentence", ["until", "heavy-precipitation", "afternoon"]],
+
+  "Oiteag shocair anns an fheasgar.":
+    ["sentence", ["during", "light-wind", "afternoon"]],
+
+  "Sneachd nas anmoiche feasgar an-diugh agus madainn a-màireach.":
+    ["sentence", ["during",
+      "medium-snow",
+      ["and", "later-today-evening", "tomorrow-morning"]]],
+
+  "Uisge trom a' stad nas anmoiche madainn an-diugh, a' tòiseachadh a-rithist feasgar an-diugh.":
+    ["sentence", ["until-starting-again",
+      "heavy-rain",
+      "later-today-morning",
+      "today-evening"]],
+
+  "Sgothan trom a' tòiseachadh anns an fheasgar, a' stad a-nochd.":
+    ["sentence", ["starting-continuing-until",
+      "heavy-clouds",
+      "evening",
+      "night"]],
+
+  "Flin aotrom nas anmoiche feasgar an-diugh agus ceòthach madainn a-màireach.":
+    ["sentence", ["and",
+      ["during", "light-sleet", "later-today-afternoon"],
+      ["during", "fog", "tomorrow-morning"]]],
+
+  "Gaoth chunnartach a' tòiseachadh madainn an-diugh, a' stad feasgar an-diugh, agus flin madainn a-màireach.":
+    ["sentence", ["and",
+      ["starting-continuing-until",
+        "heavy-wind",
+        "today-morning",
+        "today-afternoon"],
+      ["during", "medium-sleet", "tomorrow-morning"]]],
+
+  "Sgothan trom a' tòiseachadh nas anmoiche a-nochd agus sneachda trom feasgar a-màireach.":
+    ["sentence", ["and",
+      ["starting", "heavy-clouds", "later-today-night"],
+      ["during", "heavy-snow", "tomorrow-afternoon"]]],
+
+  "Tioram a-nochd agus sileadh aotrom a' tòiseachadh feasgar a-màireach, a' stad an ath oidhche.":
+    ["sentence", ["and",
+      ["during", "low-humidity", "today-night"],
+      ["starting-continuing-until",
+        "light-precipitation",
+        "tomorrow-evening",
+        "tomorrow-night"]]],
+
+  "Sneachd (5 òir.) a-nochd.":
+    ["sentence", ["during",
+      ["parenthetical", "medium-snow", ["inches", 5]],
+      "night"]],
+
+  "Sneachd aotrom (2 cm.) nas anmoiche madainn an-diugh.":
+    ["sentence", ["during",
+      ["parenthetical", "light-snow", ["centimeters", 2]],
+      "later-today-morning"]],
+
+  "Sneachda trom (8\u201312 òir.) fad an latha.":
+    ["sentence", ["for-day",
+      ["parenthetical", "heavy-snow", ["inches", ["range", 8, 12]]]]],
+
+  "Sneachd (< 1 cm.) anns an fheasgar.":
+    ["sentence", ["during",
+      ["parenthetical", "medium-snow", ["less-than", ["centimeters", 1]]],
+      "afternoon"]],
+
+
+  "Gun sileadh fad na seachdain, le an teòthachd as àirde a' ruigsinn 85\u00B0F a-màireach.":
+    ["sentence", ["with",
+      ["for-week", "no-precipitation"],
+      ["temperatures-peaking",
+        ["fahrenheit", 85],
+        "tomorrow"]]],
+
+  "Sileadh measgaichte thairis air an deireadh-sheachdain, le an teòthachd as àirde a' ruigsinn 32\u00B0C Diardaoin.":
+    ["sentence", ["with",
+      ["over-weekend", "mixed-precipitation"],
+      ["temperatures-rising",
+        ["celsius", 32],
+        "thursday"]]],
+
+  "Uisge glè aotrom Diluain, le an teòthachd as àirde a' tuiteam gu 15\u00B0F Dihaoine.":
+    ["sentence", ["with",
+      ["during", "very-light-rain", "monday"],
+      ["temperatures-valleying",
+        ["fahrenheit", 15],
+        "friday"]]],
+
+  "Sneachd aotrom Dimàirt agus Diciadain an ath sheachdain, le an teòthachd as àirde a' tuiteam gu 0\u00B0C Didòmhnaich.":
+    ["sentence", ["with",
+      ["during", "light-snow", ["and", "tuesday", "next-wednesday"]],
+      ["temperatures-falling",
+        ["celsius", 0],
+        "sunday"]]],
+
+  "Sileadh an-diugh tro Disathairne, le an teòthachd as àirde a' ruigsinn 100\u00B0F Diluain.":
+    ["sentence", ["with",
+      ["during",
+        "medium-precipitation",
+        ["through", "today", "saturday"]],
+      ["temperatures-peaking",
+        ["fahrenheit", 100],
+        "monday"]]],
+
+  "Tha cothrom ann gum bi stoirmean tàirneanaich ann Diciadain an ath sheachdain agus Diardaoin an ath sheachdain.":
+    ["sentence", ["during",
+      "possible-thunderstorm",
+        ["and", "next-wednesday", "next-thursday"]
+    ]]
+}