The five-foot-tall (152-centimetre) radio operator is one of the Philippine Coast Guard's 81 "Angels of the Sea", graduates of an all-women training programme aimed at defusing encounters in the critical waterway.

"China Coast Guard vessel 5303, this is Philippine Coast Guard vessel BRP Bagacay MRRV-4410. You are advised that you are currently sailing within the Philippine Exclusive Economic Zone," she said during an encounter videotaped last month.

"You are directed to depart immediately and notify us of your intention."

Villalon's action during the incident was precisely what the coast guard envisioned when it launched the Angels programme four years ago.

Beijing claims most of the South China Sea despite an international ruling that its assertion has no legal basis, and its coast guard has clashed repeatedly with that of the Philippines, sparking fears of an armed conflict.

"(The programme) helps with our engagement with the China Coast Guard because we are utilising women, who are naturally not aggressive, not confrontational," Coast Guard Spokesman Commodore Algier Ricafrente told AFP.

That framing of women's nature drew charges of sexism when the programme first launched in 2021.

Congresswoman Arlene Brosas argued at the time it trivialised the South China Sea dispute by suggesting "maternal" voices might calm situations.

But while Philippine geopolitics analyst Andrea Wong agreed overemphasising "female characteristics" was problematic, she told AFP the programme was a "positive effort" capable of utilising women's strengths in a real way.

"The most important thing is harnessing their full potential, whether it be their language skills (or) communication skills."

For Villalon, the radio operator, the programme's central premise needs no defending.

"A woman's patience, composure and the ability to respond or to communicate with empathy makes us unique, makes us more fit for this role," the 28-year-old told AFP.

While the Philippine Coast Guard has hundreds of operators, it is the Angels who are routinely dispatched for missions in tense areas of the South China Sea, Ricafrente said.

"Angels of the Sea is a testament that there are things that women can do more effectively than men, especially in our thrust of communicating with our maritime law enforcement counterparts," he said.

"They don't feel threatened when they talk to women."

- 'Words instead of weapons' -

Villalon said she felt proud to represent Filipinas in spaces typically dominated by men, especially with regional tensions rising.

"I focus on my job... (and) just deliver my speech," she said of her approach during encounters with Chinese vessels, adding she drew inspiration from her mother, a housewife who taught her to always stand her ground.

Villalon told AFP her Chinese counterpart's tone went from aggressive to calm as she addressed him during last month's episode near the contested Scarborough Shoal.

Spokesman Ricafrente said the coast guard was committed to exhausting every means of de-escalating tensions in the South China Sea.

"Nobody wants war, nobody wants conflict... the business of the coast guard is peace," Ricafrente said, quoting Coast Guard Commandant Ronnie Gil Gavan, who dreamt up the Angels programme while still a district commander.

Ricafrente said the coast guard hopes to train another batch of Angels this year to coincide with the arrival of new ships from Japan and France that will be used for patrols in the South China Sea.

While some question the programme's effectiveness, Villalon -- who will soon start Mandarin classes to improve her communication skills -- said she believes in the importance of using "words instead of weapons".

"I have come to realise that I am the kind of woman who is brave," Villalon said.

"Not just because I am willing to fight, but because I want to make fighting unnecessary."