Twenty-seven Members of Parliament out of the 349 in the House did not contribute to plenary discussions in the House in 2015, according to a new report.
Three of the most taciturn MPs are from Nairobi County, Mzalendo Trust reveals in its 2015 report card on MPs' performance in the National Assembly and the Senate.
And although all the senators spoke in Senate plenary sessions, Mzalendo names Nairobi Senator Mike Sonko and nominated Senator Hosea Ochwangi as the worst performers in the year under review.
Mzalendo's report claims that of the 27 MPs who did not contribute to plenary sessions in the Assembly, five have never given their maiden speech, meaning they have never ever spoken a word in the House.
Those named in the Mzalendo report include Alex Kosgey (Emgwen), who was named in a similar report last year.
Others are Kipruto Moi (Rongai), Oscar Sudi (Kapseret), Gonzi Rai (Kinango), a long serving Coast MP, and Tirus Ngahu (Kangema).
According to Mzalendo Trust, the findings reveal a continuing trend in which a third of the MPs hardly contribute anything of substance to debates in Parliament.
Mzalendo has termed MPs' performance in the year as dismissal overall.
"Although the number of speech counts in plenary discussions is not indicative of the quality of input, it could allude to low capacity to exercise their parliamentarian roles," said Ms Jessica Musila, Mzalendo Trust's executive director.
She said no single lawmaker can afford to remain silent in Parliament given the high level of poverty among Kenyans and poor services in the country.
Meanwhile, Kiminini MP Chrisantus Wamalwa Wakhungu was named the most active contributor in the National Assembly, alongside Taveta's Naomi Shaban.
In the Senate, Fatuma Dullo (nominated) and Mutula Kilonzo Jr (Makueni), were named as the leading contributors in 2015, according to the report.
The most active committee chairmen were also named in the Mzalendo report: Dr Boni Khalwale (Public Accounts Committee) in the Senate and Mr Samuel Chepkonga (Justice and Legal Affairs Committee) in the National Assembly.
The debate report card for MPs is compiled by Mzalendo.com based on the official Hansard contributions published by Parliament after each sitting.
Corruption, devolution, education, health, special interests such as youth, women and people with disabilities were among the most debated topics in the both Houses in 2015.
Other subjects were political parties, agriculture, access to justice, security, gender, infrastructure, land, tax and revenue, culture, sports, human rights, marriage, environment, mining and business.