diff --git a/spacy/cli/train.py b/spacy/cli/train.py
index 957a19ba3..be5be0f0b 100644
--- a/spacy/cli/train.py
+++ b/spacy/cli/train.py
@@ -30,8 +30,8 @@ from ..compat import json_dumps
     no_tagger=("Don't train tagger", "flag", "T", bool),
     no_parser=("Don't train parser", "flag", "P", bool),
     no_entities=("Don't train NER", "flag", "N", bool),
-    parser_multitasks=("Side objectives for parser CNN, e.g. dep dep,tag", "option", "pt", ","),
-    entity_multitasks=("Side objectives for ner CNN, e.g. dep dep,tag", "option", "et", ","),
+    parser_multitasks=("Side objectives for parser CNN, e.g. dep dep,tag", "option", "pt", str),
+    entity_multitasks=("Side objectives for ner CNN, e.g. dep dep,tag", "option", "et", str),
     gold_preproc=("Use gold preprocessing", "flag", "G", bool),
     version=("Model version", "option", "V", str),
     meta_path=("Optional path to meta.json. All relevant properties will be "
@@ -105,10 +105,12 @@ def train(lang, output_dir, train_data, dev_data, n_iter=30, n_sents=0,
             lex.is_oov = False
     for name in pipeline:
         nlp.add_pipe(nlp.create_pipe(name), name=name)
-    for objective in parser_multitasks.split(','):
-        nlp.parser.add_multitask_objective(objective)
-    for objective in entity_multitasks.split(','):
-        nlp.entity.add_multitask_objective(objective)
+    if parser_multitasks:
+        for objective in parser_multitasks.split(','):
+            nlp.parser.add_multitask_objective(objective)
+    if entity_multitasks:
+        for objective in entity_multitasks.split(','):
+            nlp.entity.add_multitask_objective(objective)
     optimizer = nlp.begin_training(lambda: corpus.train_tuples, device=use_gpu)
     nlp._optimizer = None