The track cuts out just before the second bridge of “Say You’ll Be There” by the Spice Girls. We’d been singing for two hours at this point, I could feel it in the back of my throat. We carried on for a few bars, the chart-topping track etched into the memories of millennial co-workers, when it became apparent we’d run out of time. The little sound-proofed room was trying to robotically usher us out. People noticed, then I grabbed the mic: “If you.... can’t work this equation, then I guess I’ll have to show you the door”. Lyrics carved into our brains as children staring at boxy televisions, watching the Spice Girls spin and sing in the desert in shiny minidresses. Some seconds earlier I'd stuck my phone on video and propped it up behind a sofa, and so now I have it trapped in my camera roll: a handful of thirty-somethings, singing the Spice Girls without any prompt from a screen: “I'll give you everything, on this I swear! Just promise you'll always be there!”

We shout it, somehow both grown adults and eight-year-olds at once, embodying the Spice Girl we had been designated (I was always Posh, namely due to the similarities in our haircut). We remember the melodies, the shout outs, the vocal fries. We rattle them out and the twenty-somethings stand quiet in the background. Someone pretends to be at Glastonbury. Someone else pretends to be Mel C. This was the last song, and I chose it. This was my last work Christmas Party in 13 years. I sat on the bus on the way home, thinking about getting a McDonalds, and knowing that I will miss them.

I don’t dress up for it, in the end. Wear the same Renaissance-print tube dress I wore this time last year, when the baby was ripe in my belly and testing the seams. Put on my most practical boots, the ones for wet weather. Put on my current favourite jumper, with a slogan about libraries embroidered across the front. I feed the baby and put him in his cot. I get on the bus. I hug people I’ve not seen in months, order a negroni, get coerced into singing Mr Brightside within the first 20 minutes.

I came late to karaoke. It took heartbreak and a solo trip to Japan. On my last night in Tokyo - my last night of the trip - I reunited with some Argentinians I’d met a week earlier in a ryokan in the hills. They had brought together an international group of loners. I drank beer, put on a felt carrot costume that was hanging on the rack, belted out Cher. It both made sense at the time and didn’t. This, along with a hen party where we all got too drunk too early and screeched through Taylor Swift, was the extent of my karaoke experience.

I’ve not learned the etiquette. Last week I was surprised by how many songs some people did, their sheer hunger for it: to stand behind an echoey microphone and play out those hairbrush-mirror dreams. The booths transform over a good session, from claustrophobic cells to sweatboxes, the scene of the greatest secret parties in the city. To be in one is to be sealed in. If people start to drift out, it's just a room. I suppose people go in alone sometimes and cast their own dreams against the walls.

In Japanese, Karaoke translates to “empty orchestra”; a fact I thought I came across in Absolutely on Music, a book of transcribed conversations between novelist Haruki Murakami and conductor Seiji Ozawa. Months on, I can’t find it as I flick through the pages, and perhaps this makes more sense - why would two men who are speaking Japanese to one another translate a word to English while discussing classical music? Still, I have a lightbulb memory of coming across the translation: sitting alone in a hotel restaurant in Cornwall, surrounded by people a lot older than me on holiday. I remember finding it eerie and beautiful, two words that transformed something brash and shiny and novelty into both an absence and a presence at once.

On a previous trip to Japan I’d walked around the downtown of Osaka and seen a group of elderly men huddled around a karaoke machine in a cafe in the middle of the day. I’d seen microphones etched into gravestones. Later, in London, a friend of mine told me he once went to a karaoke bar alone, fully trusting that he would find a crowd and a song and a moment the same way other people perhaps take a nightcap or chance on a stranger’s party. Some people find love that way, others regret. To me it seemed courageous, knowing what you want lies at the end of a microphone in a padded room.

In the days afterwards videos and text messages ricocheted around between us; I’d not been the only one who had videoed bits of the night. But the earworms lasted longer. As I type this, a near-week on, I still have snatches of Dolly Parton’s ‘9 To 5’ (a naive karaoke choice, it’s bloody fast) peppering my thoughts. As we walked back from the park on the weekend I let out a few bars of ‘Foundations’ by Kate Nash (an inspired one, given the crowd). I’m not sure where the orchestra is; the tinny soundtracks are absent in these internal soundscapes. Instead, I hear choruses, I hear the ghosts of the original songs. They are time portals that we are making anew all the time.