[egs] egs/tedlium/s5_r2 download Tedlium LMs from kaldi-asr.org (#2441)

egs/tedlium/s5_r2/local/ted_download_lm.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+#
+# Copyright  2018  David Snyder
+# Apache 2.0
+#
+# This script downloads pre-built language models trained on the Cantab-Tedlium
+# text data and Tedlium acoustic training data.  If you want to build these
+# models yourself, run the script local/ted_train_lm.sh.
+
+set -e
+
+echo "$0: downloading Tedlium 4 gram language models (it won't re-download if it was already downloaded.)"
+wget --continue http://kaldi-asr.org/models/5/4gram_small.arpa.gz -P data/local/local_lm/data/arpa || exit 1
+wget --continue http://kaldi-asr.org/models/5/4gram_big.arpa.gz -P data/local/local_lm/data/arpa || exit 1
+
+exit 0
+

egs/tedlium/s5_r2/run.sh

@@ -57,10 +57,12 @@ if [ $stage -le 3 ]; then
 fi
 
 if [ $stage -le 4 ]; then
-  # later on we'll change this script so you have the option to
-  # download the pre-built LMs from openslr.org instead of building them
+  # Download the pre-built LMs from kaldi-asr.org instead of building them
   # locally.
-  local/ted_train_lm.sh
+  local/ted_download_lm.sh
+  # Uncomment this script to build the language models instead of
+  # downloading them from kaldi-asr.org.
+  # local/ted_train_lm.sh
 fi
 
 if [ $stage -le 5 ]; then