diff --git a/silk/API.h b/silk/API.h
index c77ad2f5bf4ff694222d3348f5e0bb9133aef6d9..4b8ca12ac667792d0ae421d93c70baeb86f04eca 100644
--- a/silk/API.h
+++ b/silk/API.h
@@ -67,14 +67,6 @@ opus_int silk_InitEncoder(                              /* O    Returns error co
     silk_EncControlStruct           *encStatus          /* O    Encoder Status                                  */
 );
 
-/***************************************/
-/* Read control structure from encoder */
-/***************************************/
-opus_int silk_QueryEncoder(                             /* O    Returns error code                              */
-    const void                      *encState,          /* I    State                                           */
-    silk_EncControlStruct           *encStatus          /* O    Encoder Status                                  */
-);
-
 /**************************/
 /* Encode frame with Silk */
 /**************************/
diff --git a/silk/control_codec.c b/silk/control_codec.c
index d0ed528fcd633e3d1c957bc58e622ff8b71e85ef..ecc338cec65d6e32fbe09f7c6312a275329de6d5 100644
--- a/silk/control_codec.c
+++ b/silk/control_codec.c
@@ -38,18 +38,18 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "tuning_parameters.h"
 #include "pitch_est_defines.h"
 
-opus_int silk_setup_resamplers(
+static opus_int silk_setup_resamplers(
     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
     opus_int                        fs_kHz              /* I                        */
 );
 
-opus_int silk_setup_fs(
+static opus_int silk_setup_fs(
     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
     opus_int                        fs_kHz,             /* I                        */
     opus_int                        PacketSize_ms       /* I                        */
 );
 
-opus_int silk_setup_complexity(
+static opus_int silk_setup_complexity(
     silk_encoder_state              *psEncC,            /* I/O                      */
     opus_int                        Complexity          /* I                        */
 );
@@ -131,7 +131,7 @@ opus_int silk_control_encoder(
     return ret;
 }
 
-opus_int silk_setup_resamplers(
+static opus_int silk_setup_resamplers(
     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
     opus_int                         fs_kHz              /* I                        */
 )
@@ -186,7 +186,7 @@ opus_int silk_setup_resamplers(
     return ret;
 }
 
-opus_int silk_setup_fs(
+static opus_int silk_setup_fs(
     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
     opus_int                        fs_kHz,             /* I                        */
     opus_int                        PacketSize_ms       /* I                        */
@@ -299,7 +299,7 @@ opus_int silk_setup_fs(
     return ret;
 }
 
-opus_int silk_setup_complexity(
+static opus_int silk_setup_complexity(
     silk_encoder_state              *psEncC,            /* I/O                      */
     opus_int                        Complexity          /* I                        */
 )
diff --git a/silk/enc_API.c b/silk/enc_API.c
index c0143fd5a02b27beff68a9fd33e5d8c9da2d01cb..ec7915ce242e064a23a864d1a13b64783d832d34 100644
--- a/silk/enc_API.c
+++ b/silk/enc_API.c
@@ -40,6 +40,14 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "main_FLP.h"
 #endif
 
+/***************************************/
+/* Read control structure from encoder */
+/***************************************/
+static opus_int silk_QueryEncoder(                      /* O    Returns error code                              */
+    const void                      *encState,          /* I    State                                           */
+    silk_EncControlStruct           *encStatus          /* O    Encoder Status                                  */
+);
+
 /****************************************/
 /* Encoder functions                    */
 /****************************************/
@@ -90,7 +98,7 @@ opus_int silk_InitEncoder(                              /* O    Returns error co
 /***************************************/
 /* Read control structure from encoder */
 /***************************************/
-opus_int silk_QueryEncoder(                             /* O    Returns error code                              */
+static opus_int silk_QueryEncoder(                      /* O    Returns error code                              */
     const void                      *encState,          /* I    State                                           */
     silk_EncControlStruct           *encStatus          /* O    Encoder Status                                  */
 )
diff --git a/silk/float/prefilter_FLP.c b/silk/float/prefilter_FLP.c
index 95b32da5800dda878bce93bc635954ec4e4e51a8..d6c843987e07d53a1a1adaa66e7550d81a1174dd 100644
--- a/silk/float/prefilter_FLP.c
+++ b/silk/float/prefilter_FLP.c
@@ -47,7 +47,7 @@ static inline void silk_prefilt_FLP(
     opus_int                    length              /* I */
 );
 
-void silk_warped_LPC_analysis_filter_FLP(
+static void silk_warped_LPC_analysis_filter_FLP(
           silk_float                 state[],            /* I/O  State [order + 1]                       */
           silk_float                 res[],              /* O    Residual signal [length]                */
     const silk_float                 coef[],             /* I    Coefficients [order]                    */
diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index b77e48e620cb20919553d193bff503eb288c060f..ea6bfa399be8b7f39da019d34c8f28d37087f862 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -291,7 +291,7 @@ static unsigned char gen_toc(int mode, int framerate, int bandwidth, int channel
 }
 
 #ifndef FIXED_POINT
-void silk_biquad_float(
+static void silk_biquad_float(
     const opus_val16      *in,            /* I:    Input signal                   */
     const opus_int32      *B_Q28,         /* I:    MA coefficients [3]            */
     const opus_int32      *A_Q28,         /* I:    AR coefficients [2]            */