If you call this with argument "unused=true" it searches for the translation strings that exist in en_US but are never used.
IMPORTANT: that can take quite a lot of time (up to 10 minutes), you need to tune the max_execution_time on your php.ini accordingly.

Duplicate strings in lang files in /home/clubttbeaq/www/apps/dev/translation/../../htdocs/langs/en_US/ - 96 found

#StringFile and lines
56NotTheAssignedApproverholiday.lang (74 - You are not the assigned approver) (98 - You are not the assigned approver)
62CurrentValuemain.lang (211 - Current value) (668 - Current value)
2ByYearaccountancy.lang (173 - By year)
main.lang (768 - By year)
16Browseradmin.lang (985 - Browser)
main.lang (690 - Browser)
31Eventsagenda.lang (12 - Events)
main.lang (865 - Events)
43ValidatePaymentbills.lang (92 - Validate payment)
main.lang (718 - Validate payment)
57IncotermLabelincoterm.lang (3 - Incoterms)
main.lang (879 - Incoterms)
59StatusInterInvoicedinterventions.lang (31 - Billed)
main.lang (490 - )
60Closedmain.lang (141 - Closed)
ticket.lang (65 - Closed)
61NewObjectmain.lang (209 - New %s)
modulebuilder.lang (9 - New object)
63Typemain.lang (213 - Type)
ticket.lang (69 - Type)
64MulticurrencyPaymentAmountmain.lang (356 - Payment amount, original currency)
multicurrency.lang (19 - Payment amount, original currency)
65Categorymain.lang (468 - Tag/category)
ticket.lang (70 - Category)
66NotReadmain.lang (643 - Not read)
ticket.lang (59 - Not read)
5InternalUseradmin.lang (48 - Internal user)
users.lang (68 - Internal user)
6NewModuleadmin.lang (203 - New)
modulebuilder.lang (8 - New module)
7NoticePeriodadmin.lang (261 - Notice period)
holiday.lang (110 - Notice period)
8LanguageFileadmin.lang (358 - Language file)
modulebuilder.lang (49 - File for language)
9Stringadmin.lang (399 - String)
members.lang (101 - String)
10Intadmin.lang (402 - Integer)
members.lang (103 - Int)
11DateAndTimeadmin.lang (404 - Date and hour)
members.lang (104 - Date and time)
12Fieldadmin.lang (473 - Field)
blockedlog.lang (2 - Field)
exports.lang (60 - Field)
13Module62000Nameadmin.lang (639 - Incoterms)
incoterm.lang (1 - Incoterm)
14Module62000Descadmin.lang (640 - Add features to manage Incoterms)
incoterm.lang (2 - Add features to manage Incoterm)
15Upgradeadmin.lang (974 - Upgrade)
install.lang (102 - Upgrade)
17Serveradmin.lang (986 - Server)
install.lang (47 - Server)
18DatabaseServeradmin.lang (988 - Database host)
install.lang (50 - Database server)
19DatabaseNameadmin.lang (989 - Database name)
install.lang (51 - Database name)
20DriverTypeadmin.lang (997 - Driver type)
install.lang (46 - Driver type)
21CompanyNameadmin.lang (1018 - Name)
companies.lang (26 - Company name)
22CreditNoteadmin.lang (1233 - Credit note)
bills.lang (285 - Credit note)
23CreditNotesadmin.lang (1234 - Credit notes)
bills.lang (286 - Credit notes)
24WithdrawalsSetupadmin.lang (1498 - Setup of module Direct debit payment orders)
withdrawals.lang (22 - Direct debit payment setup)
25Buyadmin.lang (1584 - Buy)
products.lang (48 - Purchases)
26Selladmin.lang (1585 - Sell)
products.lang (47 - Sales)
27AccountancyCodeadmin.lang (1588 - Accounting Code)
companies.lang (305 - Accounting account)
28CashDeskadmin.lang (1611 - Point of sales)
cashdesk.lang (3 - Point of sale)
29ByDefaultInListadmin.lang (1758 - Show by default on list view)
categories.lang (89 - By default in list)
1LineIdaccountancy.lang (117 - Id line)
exports.lang (41 - Id of line)
3CustomerInvoicePaymentaccountancy.lang (189 - Payment of invoice customer)
banks.lang (100 - Customer payment)
4Natureaccountancy.lang (247 - Nature)
members.lang (174 - Nature)
products.lang (161 - Nature)
30AffectedToagenda.lang (10 - Assigned to)
projects.lang (107 - Allocated to)
32Locationagenda.lang (16 - Location)
stocks.lang (34 - Location)
33InterventionSentByEMailagenda.lang (80 - Intervention %s sent by EMail)
interventions.lang (39 - Intervention %s sent by EMail)
34DeleteTypeassets.lang (29 - Delete)
members.lang (76 - Delete)
35ShowTypeCardassets.lang (32 - Show type '%s')
members.lang (144 - Show type '%s')
36IBANbanks.lang (32 - IBAN number)
bills.lang (426 - IBAN)
37BICbanks.lang (33 - BIC/SWIFT number)
bills.lang (427 - BIC/SWIFT)
38StandingOrdersbanks.lang (38 - Direct Debit orders)
bills.lang (232 - Direct debit orders)
39StandingOrderbanks.lang (39 - Direct debit order)
bills.lang (233 - Direct debit order)
40Accountbanks.lang (64 - Account)
compta.lang (15 - Account)
41SubscriptionPaymentbanks.lang (102 - Subscription payment)
members.lang (158 - Subscription payment)
42Paymentsbills.lang (63 - Payments)
compta.lang (83 - Payments)
44InvoiceRefbills.lang (314 - Invoice ref.)
compta.lang (208 - Invoice ref.)
45NoSupplierOrderboxes.lang (67 - No recorded supplier order)
orders.lang (78 - No purchase order)
46ShowCompanycashdesk.lang (29 - Show company)
companies.lang (321 - Show Third Party)
47DeleteFromCatcategories.lang (82 - Remove from tags/category)
compta.lang (250 - Remove from accounting group)
48Customercommercial.lang (4 - Customer)
companies.lang (268 - Customer)
49Prospectcommercial.lang (6 - Prospect)
companies.lang (266 - Prospect)
propal.lang (12 - Prospect)
50ShowTaskcommercial.lang (18 - Show task)
projects.lang (39 - Show task)
51ToPaycompta.lang (66 - To pay)
paybox.lang (14 - Do payment)
52ContractStatusClosedcontracts.lang (9 - Closed)
products.lang (75 - Closed)
53ExportsAreaexports.lang (2 - Exports)
other.lang (253 - Exports area)
54ExportableDatasexports.lang (6 - Exportable dataset)
other.lang (257 - Exportable data)
55AvailableFormatsexports.lang (27 - Available Formats)
other.lang (254 - Available formats)
58CreateUserinstall.lang (58 - Create user account or grant user account permission on the Dolibarr database)
users.lang (30 - Create user)
67OrderDateorders.lang (10 - Order date)
suppliers.lang (9 - Order date)
68CreatedByother.lang (108 - Created by %s)
ticket.lang (146 - Created by)
69FollowingUrlAreAvailableToMakePaymentspaybox.lang (4 - Following URLs are available to offer a page to a customer to make a payment on Dolibarr objects)
stripe.lang (5 - Following URLs are available to offer a page to a customer to make a payment on Dolibarr objects)
70PaymentFormpaybox.lang (5 - Payment form)
stripe.lang (6 - Payment form)
71WelcomeOnPaymentPagepaybox.lang (6 - Welcome to our online payment service)
stripe.lang (7 - Welcome to our online payment service)
72ThisScreenAllowsYouToPaypaybox.lang (7 - This screen allow you to make an online payment to %s.)
stripe.lang (8 - This screen allow you to make an online payment to %s.)
73ThisIsInformationOnPaymentpaybox.lang (8 - This is information on payment to do)
stripe.lang (9 - This is information on payment to do)
74ToCompletepaybox.lang (9 - To complete)
stripe.lang (10 - To complete)
75YourEMailpaybox.lang (10 - Email to receive payment confirmation)
stripe.lang (11 - Email to receive payment confirmation)
76Creditorpaybox.lang (11 - Creditor)
stripe.lang (13 - Creditor)
77PaymentCodepaybox.lang (12 - Payment code)
stripe.lang (14 - Payment code)
78Continuepaybox.lang (16 - Next)
stripe.lang (17 - Next)
79ToOfferALinkForOnlinePaymentpaybox.lang (17 - URL for %s payment)
stripe.lang (18 - URL for %s payment)
80ToOfferALinkForOnlinePaymentOnOrderpaybox.lang (18 - URL to offer a %s online payment user interface for a customer order)
stripe.lang (19 - URL to offer a %s online payment user interface for a customer order)
81ToOfferALinkForOnlinePaymentOnInvoicepaybox.lang (19 - URL to offer a %s online payment user interface for a customer invoice)
stripe.lang (20 - URL to offer a %s online payment user interface for a customer invoice)
82ToOfferALinkForOnlinePaymentOnContractLinepaybox.lang (20 - URL to offer a %s online payment user interface for a contract line)
stripe.lang (21 - URL to offer a %s online payment user interface for a contract line)
83ToOfferALinkForOnlinePaymentOnFreeAmountpaybox.lang (21 - URL to offer a %s online payment user interface for a free amount)
stripe.lang (22 - URL to offer a %s online payment user interface for a free amount)
84ToOfferALinkForOnlinePaymentOnMemberSubscriptionpaybox.lang (22 - URL to offer a %s online payment user interface for a member subscription)
stripe.lang (23 - URL to offer a %s online payment user interface for a member subscription)
85YouCanAddTagOnUrlpaybox.lang (24 - You can also add url parameter <b>&tag)
stripe.lang (24 - You can also add url parameter <b>&tag)
86AccountParameterpaybox.lang (28 - Account parameters)
stripe.lang (26 - Account parameters)
87UsageParameterpaybox.lang (29 - Usage parameters)
stripe.lang (27 - Usage parameters)
88InformationToFindParameterspaybox.lang (30 - Help to find your %s account information)
stripe.lang (28 - Help to find your %s account information)
89VendorNamepaybox.lang (32 - Name of vendor)
stripe.lang (30 - Name of vendor)
90CSSUrlForPaymentFormpaybox.lang (33 - CSS style sheet url for payment form)
stripe.lang (31 - CSS style sheet url for payment form)
91Stockproducts.lang (44 - Stock)
stocks.lang (18 - Stock)
92Stocksproducts.lang (45 - Stocks)
stocks.lang (19 - Stocks)
93Movementsproducts.lang (46 - Movements)
stocks.lang (23 - Movements)
94Suppliersproducts.lang (80 - Suppliers)
suppliers.lang (2 - Vendors)
95ListOfStockMovementsproducts.lang (87 - List of stock movements)
stocks.lang (26 - List of stock movements)
96Unitproducts.lang (163 - Unit)
stocks.lang (41 - Unit)