diff --git a/lib/dictBuilder/cover.c b/lib/dictBuilder/cover.c
index 9e5e7d5b55d..e7fcfd2099b 100644
--- a/lib/dictBuilder/cover.c
+++ b/lib/dictBuilder/cover.c
@@ -733,7 +733,7 @@ static size_t COVER_buildDictionary(const COVER_ctx_t *ctx, U32 *freqs,
   return tail;
 }
 
-ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover(
+ZDICTLIB_STATIC_API size_t ZDICT_trainFromBuffer_cover(
     void *dictBuffer, size_t dictBufferCapacity,
     const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples,
     ZDICT_cover_params_t parameters)
@@ -1119,7 +1119,7 @@ static void COVER_tryParameters(void *opaque)
   free(freqs);
 }
 
-ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover(
+ZDICTLIB_STATIC_API size_t ZDICT_optimizeTrainFromBuffer_cover(
     void* dictBuffer, size_t dictBufferCapacity, const void* samplesBuffer,
     const size_t* samplesSizes, unsigned nbSamples,
     ZDICT_cover_params_t* parameters)
diff --git a/lib/dictBuilder/fastcover.c b/lib/dictBuilder/fastcover.c
index 46bba0120b0..a958eb337f1 100644
--- a/lib/dictBuilder/fastcover.c
+++ b/lib/dictBuilder/fastcover.c
@@ -545,7 +545,7 @@ FASTCOVER_convertToFastCoverParams(ZDICT_cover_params_t coverParams,
 }
 
 
-ZDICTLIB_API size_t
+ZDICTLIB_STATIC_API size_t
 ZDICT_trainFromBuffer_fastCover(void* dictBuffer, size_t dictBufferCapacity,
                                 const void* samplesBuffer,
                                 const size_t* samplesSizes, unsigned nbSamples,
@@ -614,7 +614,7 @@ ZDICT_trainFromBuffer_fastCover(void* dictBuffer, size_t dictBufferCapacity,
 }
 
 
-ZDICTLIB_API size_t
+ZDICTLIB_STATIC_API size_t
 ZDICT_optimizeTrainFromBuffer_fastCover(
                     void* dictBuffer, size_t dictBufferCapacity,
                     const void* samplesBuffer,