  Non-native English speakers (NNESs) often face challenges in achieving
fluency in their written English. AI paraphrasing tools have the potential to
improve their writing by suggesting more fluent paraphrases to their original
sentences. Yet, the effectiveness of these tools depends on the user's ability
to accurately assess and select context-appropriate suggestions, which is a
significant challenge for those with limited English proficiency. This paper
explores how NNESs utilize a paraphrasing tool augmented with information aids
designed to facilitate the assessment of paraphrased suggestions. Through a
formative study with 15 NNESs, we identify their specific needs when
paraphrasing with AI, leading to the design of a paraphrasing tool integrated
with five types of information aids, termed "support features." A user study
with 22 NNESs demonstrates their heavy reliance on the paraphrasing
functionality throughout the writing process, where they leverage the support
features to assess and select suggestions efficiently and comprehensively. When
equipped with the support features, NNESs experience enhanced writing
experience in efficiency, confidence, and trust. Our findings contribute to the
HCI community by (i) identifying the distinct needs of NNESs in AI paraphrasing
tools, (ii) elucidating how NNESs use paraphrasing tools with support features,
and (iii) offering design implications for the development of more effective AI
paraphrasing tools tailored to NNESs' requirements.
