Not much to translate here, but why not. Internationalization library support.

depends.txt

@@ -1 +1,2 @@
-default?
+default?
+intllib?

init.lua

@@ -1,5 +1,9 @@
 dynamic_liquid = {} -- global table to expose liquid_abm for other mods' usage
 
+-- internationalization boilerplate
+local MP = minetest.get_modpath(minetest.get_current_modname())
+local S, NS = dofile(MP.."/intllib.lua")
+
 -- By making this giant table of all possible permutations of horizontal direction we can avoid
 -- lots of redundant calculations.
 local all_direction_permutations = {
@@ -134,7 +138,7 @@ end
 -- register damp clay whether we're going to set the ABM or not, if the user disables this feature we don't want existing
 -- spring clay to turn into unknown nodes.
 local clay_def = duplicate_def("default:clay")
-clay_def.description = "Damp Clay"
+clay_def.description = S("Damp Clay")
 if not springs then
 	clay_def.groups.not_in_creative_inventory = 1 -- take it out of creative inventory though
 end
@@ -190,7 +194,7 @@ if springs then
 	-- This is a creative-mode only node that produces a modest amount of water continuously no matter where it is.
 	-- Allow this one to turn into "unknown node" when this feature is disabled, since players had to explicitly place it.
 	minetest.register_node("dynamic_liquid:spring", {
-	description = "Spring",
+	description = S("Spring"),
 	drops = "default:gravel",
 	tiles = {"default_cobble.png^[combine:16x80:0,-48=crack_anylength.png",
 		"default_cobble.png","default_cobble.png","default_cobble.png","default_cobble.png","default_cobble.png",

intllib.lua

@@ -0,0 +1,45 @@
+
+-- Fallback functions for when `intllib` is not installed.
+-- Code released under Unlicense <http://unlicense.org>.
+
+-- Get the latest version of this file at:
+--   https://raw.githubusercontent.com/minetest-mods/intllib/master/lib/intllib.lua
+
+local function format(str, ...)
+	local args = { ... }
+	local function repl(escape, open, num, close)
+		if escape == "" then
+			local replacement = tostring(args[tonumber(num)])
+			if open == "" then
+				replacement = replacement..close
+			end
+			return replacement
+		else
+			return "@"..open..num..close
+		end
+	end
+	return (str:gsub("(@?)@(%(?)(%d+)(%)?)", repl))
+end
+
+local gettext, ngettext
+if minetest.get_modpath("intllib") then
+	if intllib.make_gettext_pair then
+		-- New method using gettext.
+		gettext, ngettext = intllib.make_gettext_pair()
+	else
+		-- Old method using text files.
+		gettext = intllib.Getter()
+	end
+end
+
+-- Fill in missing functions.
+
+gettext = gettext or function(msgid, ...)
+	return format(msgid, ...)
+end
+
+ngettext = ngettext or function(msgid, msgid_plural, n, ...)
+	return format(n==1 and msgid or msgid_plural, ...)
+end
+
+return gettext, ngettext

locale/de.po

@@ -0,0 +1,25 @@
+# Dynamic liquid Minetest mod.
+# Copyright (C) 2017
+# This file is distributed under the same license as the dynamic_liquid package.
+# FaceDeer
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2017-02-02 20:18-0700\n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: init.lua:141
+msgid "Damp Clay"
+msgstr "Feuchten Lehm"
+
+#: init.lua:197
+msgid "Spring"
+msgstr "Quelle"

locale/es.po

@@ -0,0 +1,25 @@
+# Dynamic liquid Minetest mod.
+# Copyright (C) 2017
+# This file is distributed under the same license as the dynamic_liquid package.
+# FaceDeer
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2017-02-02 20:18-0700\n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: init.lua:141
+msgid "Damp Clay"
+msgstr "Arcilla húmeda"
+
+#: init.lua:197
+msgid "Spring"
+msgstr "Manantial"

locale/fr.po

@@ -0,0 +1,25 @@
+# Dynamic liquid Minetest mod.
+# Copyright (C) 2017
+# This file is distributed under the same license as the dynamic_liquid package.
+# FaceDeer
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2017-02-02 20:18-0700\n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: init.lua:141
+msgid "Damp Clay"
+msgstr "Argile humide"
+
+#: init.lua:197
+msgid "Spring"
+msgstr "Source"

locale/template.pot

@@ -0,0 +1,25 @@
+# Dynamic liquid Minetest mod.
+# Copyright (C) 2017
+# This file is distributed under the same license as the dynamic_liquid package.
+# FaceDeer
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2017-02-02 20:18-0700\n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: init.lua:141
+msgid "Damp Clay"
+msgstr ""
+
+#: init.lua:197
+msgid "Spring"
+msgstr ""