Add parquet file description

README.md

@@ -39,9 +39,15 @@ The sentences included in the dataset are in Catalan (CA) and Portuguese (PT).
 
 ### Data Instances
 
-A single tsv file is provided with the sentences sorted in the same order and 
-a header containing the two-letter ISO language code for the language in each column:
-ca-pt_2023_09_01_full.tsv.
+Two separate txt files are provided with the sentences sorted in the same order:
+
+- ca-pt_2023_09_01_full.ca
+- ca-pt_2023_09_01_full.pt
+
+The dataset is additionally provided in parquet format: ca-pt_2023_09_01_full.parquet.
+
+The parquet file contains two columns of parallel text obtained from the two original text files. 
+Each row in the file represents a pair of parallel sentences in the two languages of the dataset.
 
 
 ### Data Fields