diff --git a/moses/LM/Implementation.cpp b/moses/LM/Implementation.cpp
index eb67100ca..c8fc5df32 100644
--- a/moses/LM/Implementation.cpp
+++ b/moses/LM/Implementation.cpp
@@ -41,7 +41,8 @@ using namespace std;
 namespace Moses
 {
 LanguageModelImplementation::LanguageModelImplementation(const std::string &line)
-  :LanguageModel(line)
+:LanguageModel(line)
+,m_nGramOrder(NOT_FOUND)
 {
 }
 
diff --git a/moses/LM/SkeletonLM.cpp b/moses/LM/SkeletonLM.cpp
index 23958e688..f944de23a 100644
--- a/moses/LM/SkeletonLM.cpp
+++ b/moses/LM/SkeletonLM.cpp
@@ -11,6 +11,9 @@ SkeletonLM::SkeletonLM(const std::string &line)
 {
   ReadParameters();
 
+  UTIL_THROW_IF2(m_nGramOrder == NOT_FOUND, "Must set order");
+  UTIL_THROW_IF2(m_nGramOrder <= 1, "Ngram order must be more than 1");
+
   FactorCollection &factorCollection = FactorCollection::Instance();
 
   // needed by parent language model classes. Why didn't they set these themselves?