diff --git a/src/Serval/src/Serval.Translation/Services/EngineService.cs b/src/Serval/src/Serval.Translation/Services/EngineService.cs
index 5b3d08ff..9f16d939 100644
--- a/src/Serval/src/Serval.Translation/Services/EngineService.cs
+++ b/src/Serval/src/Serval.Translation/Services/EngineService.cs
@@ -681,12 +681,12 @@ pretranslateCorpus is null
                 );
             }
         }
-        return new V1.ParallelCorpus
-        {
-            Id = source.Id,
-            SourceCorpora = { sourceCorpus },
-            TargetCorpora = { targetCorpus }
-        };
+        V1.ParallelCorpus corpus = new() { Id = source.Id };
+        if (sourceCorpus.Files.Count > 0)
+            corpus.SourceCorpora.Add(sourceCorpus);
+        if (targetCorpus.Files.Count > 0)
+            corpus.TargetCorpora.Add(targetCorpus);
+        return corpus;
     }
 
     private V1.ParallelCorpus Map(
diff --git a/src/Serval/test/Serval.E2ETests/ServalClientHelper.cs b/src/Serval/test/Serval.E2ETests/ServalClientHelper.cs
index d64fb15a..95c322da 100644
--- a/src/Serval/test/Serval.E2ETests/ServalClientHelper.cs
+++ b/src/Serval/test/Serval.E2ETests/ServalClientHelper.cs
@@ -177,12 +177,22 @@ public async Task<string> AddTextCorpusToEngineAsync(
         bool pretranslate
     )
     {
-        List<DataFile> sourceFiles = await UploadFilesAsync(filesToAdd, FileFormat.Text, sourceLanguage);
+        List<DataFile> sourceFiles = await UploadFilesAsync(
+            filesToAdd,
+            FileFormat.Text,
+            sourceLanguage,
+            isTarget: false
+        );
 
         var targetFileConfig = new List<TranslationCorpusFileConfig>();
         if (!pretranslate)
         {
-            List<DataFile> targetFiles = await UploadFilesAsync(filesToAdd, FileFormat.Text, targetLanguage);
+            List<DataFile> targetFiles = await UploadFilesAsync(
+                filesToAdd,
+                FileFormat.Text,
+                targetLanguage,
+                isTarget: true
+            );
             foreach (var item in targetFiles.Select((file, i) => new { i, file }))
             {
                 targetFileConfig.Add(
@@ -193,20 +203,11 @@ bool pretranslate
 
         var sourceFileConfig = new List<TranslationCorpusFileConfig>();
 
-        if (sourceLanguage == targetLanguage && !pretranslate)
-        {
-            // if it's the same language, and we are not pretranslating, do nothing (echo for suggestions)
-            // if pretranslating, we need to upload the source separately
-            // if different languages, we are not echoing.
-        }
-        else
+        for (int i = 0; i < sourceFiles.Count; i++)
         {
-            for (int i = 0; i < sourceFiles.Count; i++)
-            {
-                sourceFileConfig.Add(
-                    new TranslationCorpusFileConfig { FileId = sourceFiles[i].Id, TextId = filesToAdd[i] }
-                );
-            }
+            sourceFileConfig.Add(
+                new TranslationCorpusFileConfig { FileId = sourceFiles[i].Id, TextId = filesToAdd[i] }
+            );
         }
 
         TranslationCorpus response = await TranslationEnginesClient.AddCorpusAsync(
@@ -239,12 +240,22 @@ public async Task<string> AddParallelTextCorpusToEngineAsync(
         bool pretranslate
     )
     {
-        List<DataFile> sourceFiles = await UploadFilesAsync(filesToAdd, FileFormat.Text, sourceLanguage);
+        List<DataFile> sourceFiles = await UploadFilesAsync(
+            filesToAdd,
+            FileFormat.Text,
+            sourceLanguage,
+            isTarget: false
+        );
 
         var targetFileConfig = new List<CorpusFileConfig>();
         if (!pretranslate)
         {
-            List<DataFile> targetFiles = await UploadFilesAsync(filesToAdd, FileFormat.Text, targetLanguage);
+            List<DataFile> targetFiles = await UploadFilesAsync(
+                filesToAdd,
+                FileFormat.Text,
+                targetLanguage,
+                isTarget: true
+            );
             foreach (var item in targetFiles.Select((file, i) => new { i, file }))
             {
                 targetFileConfig.Add(new CorpusFileConfig { FileId = item.file.Id, TextId = filesToAdd[item.i] });
@@ -263,18 +274,9 @@ bool pretranslate
 
         var sourceFileConfig = new List<CorpusFileConfig>();
 
-        if (sourceLanguage == targetLanguage && !pretranslate)
-        {
-            // if it's the same language, and we are not pretranslating, do nothing (echo for suggestions)
-            // if pretranslating, we need to upload the source separately
-            // if different languages, we are not echoing.
-        }
-        else
+        for (int i = 0; i < sourceFiles.Count; i++)
         {
-            for (int i = 0; i < sourceFiles.Count; i++)
-            {
-                sourceFileConfig.Add(new CorpusFileConfig { FileId = sourceFiles[i].Id, TextId = filesToAdd[i] });
-            }
+            sourceFileConfig.Add(new CorpusFileConfig { FileId = sourceFiles[i].Id, TextId = filesToAdd[i] });
         }
 
         CorpusConfig sourceCorpusConfig =
@@ -305,7 +307,8 @@ bool pretranslate
     public async Task<List<DataFile>> UploadFilesAsync(
         IEnumerable<string> filesToAdd,
         FileFormat fileFormat,
-        string language
+        string language,
+        bool isTarget
     )
     {
         string languageFolder = Path.GetFullPath(
@@ -325,7 +328,7 @@ string language
 
         foreach (string fileName in filesToAdd)
         {
-            string fullName = _prefix + language + "_" + fileName;
+            string fullName = _prefix + language + "_" + fileName + (isTarget ? "_trg" : "_src");
 
             //delete files that have the name name
             if (filenameToId.Contains(fullName))
diff --git a/src/ServiceToolkit/src/SIL.ServiceToolkit/Utils/ParallelCorpusPreprocessor.cs b/src/ServiceToolkit/src/SIL.ServiceToolkit/Utils/ParallelCorpusPreprocessor.cs
index c7d82728..95332e6a 100644
--- a/src/ServiceToolkit/src/SIL.ServiceToolkit/Utils/ParallelCorpusPreprocessor.cs
+++ b/src/ServiceToolkit/src/SIL.ServiceToolkit/Utils/ParallelCorpusPreprocessor.cs
@@ -161,7 +161,9 @@ row.Ref is not ScriptureRef sr
             foreach (
                 Row row in AlignPretranslateCorpus(
                     sourcePretranslateCorpora,
-                    targetCorpora.Select(tc => tc.TextCorpus).ToArray()
+                    targetCorpora.Length > 0
+                        ? targetCorpora.Select(tc => tc.TextCorpus).ToArray()
+                        : [new DictionaryTextCorpus()]
                 )
             )
             {