make it possible to let the sayers use speech dispatcher (see http://manpages.ubuntu.com/manpages/vivid/en/man1/speech-dispatcher.1.html), maybe somehow a library could be used (maybe with 'require')

moremesecons_sayer/init.lua

@@ -1,15 +1,65 @@
 local MAX_DISTANCE = 8
+local use_speech_dispatcher = false
 
-local function sayer_activate(pos)
+local sayer_activate
+if use_speech_dispatcher
+and minetest.is_singleplayer() -- must! executing commands with it and crashes may be possible
+and io.popen("if hash spd-say 2>/dev/null; then printf yes; fi"):read("*all") == "yes" then
+	minetest.log("info", "[moremesecons_sayer] using speech dispatcher")
 	local tab = {
-		"Sayer at pos",
+		"spd-say",
 		nil,
-		"says : "..minetest.get_meta(pos):get_string("text")
+		""
 	}
-	for _,player in pairs(minetest.get_connected_players()) do
-		if vector.distance(pos, player:getpos()) <= MAX_DISTANCE then
-			tab[2] = minetest.pos_to_string(pos)
-			minetest.chat_send_player(player:get_player_name(), table.concat(tab, " "))
+	local language = minetest.setting_get("language") or "en"
+	if language ~= "en" then
+		tab[3] = "-l "..language
+	end
+	MAX_DISTANCE = MAX_DISTANCE^2
+	function sayer_activate(pos)
+		local text = minetest.get_meta(pos):get_string("text")
+		if text == "" then
+			-- nothing to say
+			return
+		end
+		if string.find(text, '"') then
+			text = "So, singleplayer, you want to use me to execute commands? Writing quotes is not allowed!"
+		end
+		tab[2] = '"'..text..'"'
+		local ppos = minetest.get_player_by_name("singleplayer"):getpos()
+		ppos.y = ppos.y+1.625 -- camera position (without bobbing)
+		-- that here's just 1 volume means that it's mono
+		local volume = math.floor(-100*(
+			1-MAX_DISTANCE/vector.distance(pos, ppos)^2
+		+0.5))
+		if volume <= -100 then
+			-- nothing to hear
+			return
+		end
+		if volume > 0 then
+			--volume = "+"..math.min(100, volume)
+			-- volume bigger 0 somehow isn't louder, it rather tries to scream
+			volume = "+"..math.min(100, math.floor(volume/(MAX_DISTANCE-1)+0.5))
+		end
+		if volume == 0 then
+			tab[4] = nil
+		else
+			tab[4] = "-i "..volume
+		end
+		os.execute(table.concat(tab, " "))
+	end
+else
+	function sayer_activate(pos)
+		local tab = {
+			"Sayer at pos",
+			nil,
+			"says : "..minetest.get_meta(pos):get_string("text")
+		}
+		for _,player in pairs(minetest.get_connected_players()) do
+			if vector.distance(pos, player:getpos()) <= MAX_DISTANCE then
+				tab[2] = minetest.pos_to_string(pos)
+				minetest.chat_send_player(player:get_player_name(), table.concat(tab, " "))
+			end
 		end
 	end
 end