diff --git a/gtsam/nonlinear/LevenbergMarquardtOptimizer.cpp b/gtsam/nonlinear/LevenbergMarquardtOptimizer.cpp
index 08961db86..002f8b237 100644
--- a/gtsam/nonlinear/LevenbergMarquardtOptimizer.cpp
+++ b/gtsam/nonlinear/LevenbergMarquardtOptimizer.cpp
@@ -37,7 +37,7 @@ using boost::adaptors::map_values;
 
 /* ************************************************************************* */
 LevenbergMarquardtParams::VerbosityLM LevenbergMarquardtParams::verbosityLMTranslator(
-    const std::string &src) const {
+    const std::string &src) {
   std::string s = src;
   boost::algorithm::to_upper(s);
   if (s == "SILENT")
@@ -59,7 +59,7 @@ LevenbergMarquardtParams::VerbosityLM LevenbergMarquardtParams::verbosityLMTrans
 
 /* ************************************************************************* */
 std::string LevenbergMarquardtParams::verbosityLMTranslator(
-    VerbosityLM value) const {
+    VerbosityLM value) {
   std::string s;
   switch (value) {
   case LevenbergMarquardtParams::SILENT:
diff --git a/gtsam/nonlinear/LevenbergMarquardtOptimizer.h b/gtsam/nonlinear/LevenbergMarquardtOptimizer.h
index 5e8e3923c..20f9dec3c 100644
--- a/gtsam/nonlinear/LevenbergMarquardtOptimizer.h
+++ b/gtsam/nonlinear/LevenbergMarquardtOptimizer.h
@@ -41,9 +41,8 @@ public:
     SILENT = 0, TERMINATION, LAMBDA, TRYLAMBDA, TRYCONFIG, DAMPED, TRYDELTA
   };
 
-private:
-  VerbosityLM verbosityLMTranslator(const std::string &s) const;
-  std::string verbosityLMTranslator(VerbosityLM value) const;
+  static VerbosityLM verbosityLMTranslator(const std::string &s);
+  static std::string verbosityLMTranslator(VerbosityLM value);
 
 public:
 
diff --git a/gtsam/nonlinear/NonlinearOptimizerParams.cpp b/gtsam/nonlinear/NonlinearOptimizerParams.cpp
index b7ad342ca..ef0f2aa9b 100644
--- a/gtsam/nonlinear/NonlinearOptimizerParams.cpp
+++ b/gtsam/nonlinear/NonlinearOptimizerParams.cpp
@@ -14,7 +14,7 @@ namespace gtsam {
 
 /* ************************************************************************* */
 NonlinearOptimizerParams::Verbosity NonlinearOptimizerParams::verbosityTranslator(
-    const std::string &src) const {
+    const std::string &src) {
   std::string s = src;
   boost::algorithm::to_upper(s);
   if (s == "SILENT")
@@ -36,7 +36,7 @@ NonlinearOptimizerParams::Verbosity NonlinearOptimizerParams::verbosityTranslato
 
 /* ************************************************************************* */
 std::string NonlinearOptimizerParams::verbosityTranslator(
-    Verbosity value) const {
+    Verbosity value) {
   std::string s;
   switch (value) {
   case NonlinearOptimizerParams::SILENT:
diff --git a/gtsam/nonlinear/NonlinearOptimizerParams.h b/gtsam/nonlinear/NonlinearOptimizerParams.h
index cd5496209..dafc1f065 100644
--- a/gtsam/nonlinear/NonlinearOptimizerParams.h
+++ b/gtsam/nonlinear/NonlinearOptimizerParams.h
@@ -84,9 +84,8 @@ public:
     verbosity = verbosityTranslator(src);
   }
 
-private:
-  Verbosity verbosityTranslator(const std::string &s) const;
-  std::string verbosityTranslator(Verbosity value) const;
+  static Verbosity verbosityTranslator(const std::string &s) ;
+  static std::string verbosityTranslator(Verbosity value) ;
 
   // Successive Linearization Parameters