Why Scam Calls Are Always in Standard Japanese
Listen to recordings of impersonation scams or refund fraud calls, and you'll notice that scammers almost universally speak standard Japanese (kyotsugo). It is extremely rare to hear Kansai dialect, Tohoku dialect, or Kyushu dialect in a scam call. This is not coincidental - criminal organizations deliberately require standard Japanese.
The reason is straightforward: dialect reveals geographic origin. If a scammer speaks Kansai dialect, investigators can infer "this person is from the Kansai region," narrowing the search. Standard Japanese preserves anonymity and makes identification harder. The recommendation in bank transfer fraud prevention to "pay attention to voice irregularities" exists precisely because this forced standardization creates detectable unnaturalness.
Three Techniques Scammers Use to Manipulate Voice
1. Deliberately Altering Vocal Tone
In impersonation scams posing as a son, the scammer opens with excuses like "I have a cold" or "My throat is sore." This preemptively explains why the voice sounds different while also creating the impression of a "weakened son" through a low, raspy delivery. Humans tend to lower their guard around someone who seems vulnerable, prioritizing the desire to help over suspicion.
Analysis of NPA-released scam call recordings reveals that scammers typically begin in a calm tone, then drop their voice sharply when delivering the critical message - "Actually, something terrible has happened." This calculated use of vocal dynamics is designed to destabilize the victim's emotions.
2. Using Jargon to Project Authority
In scams impersonating police or bank employees, scammers deploy professional terminology liberally. "Unauthorized use of your account has been detected," "PIN verification is required for your bank card," "This is a cooperation request pursuant to an investigation warrant." This specialized language convinces victims that "this person is the real thing."
Scammers impersonating government officials study actual police and bank phone protocols, mimicking their speech patterns and vocabulary. Some criminal organizations distribute conversation manuals to new "callers" and conduct role-playing training sessions.
3. Using Time Pressure to Override Judgment
Scammers repeatedly use words like "today," "immediately," and "hurry" throughout the conversation. This strategy denies victims time for calm reflection. As discussed in characteristics of people vulnerable to scams, time pressure severely impairs human judgment. Scammers know this psychology intimately and never allow victims a moment to say "Wait a moment."
How to Detect Scams by Listening to the Voice
No matter how skillfully scammers manipulate their voice, they cannot perfectly become another person. Pay attention to these points to improve your chances of detecting fraud:
- Missing habitual phrases: Everyone has characteristic verbal habits. If familiar phrases like "um," "you know," or specific sentence-ending patterns are completely absent, be suspicious
- Unnatural forms of address: Whether a son calls his mother "okaa-san" or "mama" is fixed within families. A different form of address than usual is a red flag
- Unusual background sounds: Scammers often call from apartment rooms used as "bases," and other scammers' voices or ambient sounds may be audible in the background
- Inability to answer personal questions: "What did we eat together last week?" or "What's our cat's name?" - questions only family members can answer will stump a scammer
AI Voice Cloning - The New Threat
Recently, AI voice cloning technology has advanced rapidly, enabling the synthesis of a convincing replica of someone's voice from just seconds of audio. Cases of scammers obtaining voice samples from social media videos or voicemail greetings and using AI-synthesized voices for fraud calls have been reported overseas.
Against AI voice clones, traditional detection through "voice irregularities" may no longer be sufficient. This makes voice-independent countermeasures essential: establish a family passphrase, always hang up and call back using the real number, and keep voicemail always on. Combine multiple defense layers.
Cases Where Dialect Actually Prevented Scams
Interestingly, there are documented cases where dialect thwarted scam attempts. An elderly woman in the Tohoku region responded to a call from someone claiming to be her "son" by speaking in Tohoku dialect - the scammer couldn't keep up and hung up. In Okinawa, a victim who answered in Okinawan dialect (Uchinaaguchi) confused the scammer, and the fraud attempt failed.
Because scammers only have standard Japanese scripts, they cannot cope when addressed in dialect. While this isn't a reliable deliberate defense strategy, knowing that "scammers can only speak standard Japanese" is a useful detection clue. A compact voice recorder can help you review voice irregularities after the fact by recording calls.
Recording and Analyzing Phone Voices
Recording scam calls is extremely valuable for both post-hoc verification and suspect identification. With a recording, you can review voice irregularities in a calm state and submit decisive evidence when consulting police.
Voiceprint Analysis Technology and Potential
A voiceprint is a visualization of the frequency patterns and harmonic structures in human speech, serving as an identification clue similar to a fingerprint. Police forensic science laboratories extract voiceprints from recorded audio and compare them against suspects' voices. While voiceprint analysis cannot identify individuals with 100% accuracy, it plays an important role in narrowing investigations. Recent advances in AI-powered audio analysis are improving capabilities, and research into distinguishing synthetic speech from human voices is progressing. As AI voice clone scams increase, such analytical technology becomes ever more critical.
Legal Status of Recordings
In Japan, recording your own phone conversations is generally legal. The other party's consent is not required, and secretly recorded audio has been admitted as evidence in numerous court cases. As detailed in the legal guide to call recording, preserve recordings in their original form without editing, and store them in a format that automatically records the date and time. Keeping your smartphone's call recording app always active ensures that unexpected scam calls are automatically captured.
How to Provide Recordings to Police
When providing recordings to police, keep these points in mind. First, copy the audio file to an SD card or USB drive for reliable handoff - showing your phone screen alone may not facilitate smooth data transfer. Second, prepare a written summary including the recording date and time, the caller's phone number (if displayed), and an overview of the conversation. Police use recordings not only for voiceprint analysis but also to analyze the criminal group's organizational structure and connections to other cases. A single recording can sometimes link multiple investigations.
Follow the procedures in the Phone Scam Reporting Guide when providing recordings. Calling the police consultation line (#9110) in advance to mention you have a recording will ensure smoother handling. Recording protects not just yourself but contributes to saving other potential victims targeted by the same tactics.