data_collator = TTSDataCollatorWithPadding(processor=processor)

Train the model
Load the pre-trained model from the same checkpoint as you used for loading the processor: 

from transformers import SpeechT5ForTextToSpeech
model = SpeechT5ForTextToSpeech.from_pretrained(checkpoint)

The use_cache=True option is incompatible with gradient checkpointing. Disable it for training.
 

model.config.use_cache = False