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/alixrousqt/www/erptest/dev/translation/../../htdocs/langs/en_US/ - 62 found

#StringFile and lines
9InternalUseradmin.lang (34 - Internal user)
users.lang (65 - Internal user)
10Stringadmin.lang (339 - String)
members.lang (97 - String)
11Intadmin.lang (341 - Integer)
members.lang (99 - Int)
12DateAndTimeadmin.lang (343 - Date and hour)
members.lang (100 - Date and time)
13Upgradeadmin.lang (863 - Upgrade)
install.lang (98 - Upgrade)
14Serveradmin.lang (875 - Server)
install.lang (44 - Server)
15DatabaseServeradmin.lang (877 - Database host)
install.lang (47 - Database server)
16DatabaseNameadmin.lang (878 - Database name)
install.lang (48 - Database name)
17DriverTypeadmin.lang (886 - Driver type)
install.lang (43 - Driver type)
18CompanyNameadmin.lang (905 - Name)
companies.lang (24 - Company name)
19Miscellaneousadmin.lang (1087 - Miscellaneous)
other.lang (58 - Miscellaneous)
20CreditNoteadmin.lang (1094 - Credit note)
bills.lang (265 - Credit note)
21CreditNotesadmin.lang (1095 - Credit notes)
bills.lang (266 - Credit notes)
22WithdrawalsSetupadmin.lang (1340 - Withdrawal module setup)
withdrawals.lang (21 - Withdrawal setup)
23Buyadmin.lang (1424 - Buy)
products.lang (41 - Purchases)
24Selladmin.lang (1425 - Sell)
products.lang (40 - Sales)
25AccountancyCodeadmin.lang (1428 - Accountancy Code)
companies.lang (273 - Accountancy code)
26CashDeskadmin.lang (1445 - Point of sales)
cashdesk.lang (3 - Point of sale)
27ByDefaultInListadmin.lang (1575 - Show by default on list view)
categories.lang (81 - By default in list)
1NewAccountaccountancy.lang (28 - New accounting account)
banks.lang (48 - New account)
compta.lang (92 - New account)
2Createaccountancy.lang (29 - Create)
products.lang (13 - Create)
3DescSellsJournalaccountancy.lang (97 - Sales journal)
compta.lang (164 - Sales Journal)
4DescPurchasesJournalaccountancy.lang (98 - Purchases journal)
compta.lang (165 - Purchases Journal)
5CustomerInvoicePaymentaccountancy.lang (102 - Payment of invoice customer)
banks.lang (91 - Customer payment)
6Accountparentaccountancy.lang (118 - Root of the account)
compta.lang (16 - Account parent)
7Exportsaccountancy.lang (144 - Exports)
members.lang (155 - Exports)
8Exportaccountancy.lang (145 - Export)
other.lang (223 - Export)
28Calendaragenda.lang (6 - Calendar)
other.lang (3 - Calendar)
29AffectedToagenda.lang (10 - Assigned to)
projects.lang (91 - Allocated to)
30Locationagenda.lang (15 - Location)
stocks.lang (23 - Location)
31PropalValidatedInDolibarragenda.lang (37 - Proposal %s validated)
other.lang (209 - Proposal %s validated)
32InvoiceValidatedInDolibarragenda.lang (38 - Invoice %s validated)
other.lang (211 - Invoice %s validated)
33InterventionSentByEMailagenda.lang (56 - Intervention %s sent by EMail)
interventions.lang (38 - Intervention %s sent by EMail)
34NewCompanyToDolibarragenda.lang (60 - Third party created)
other.lang (205 - Company %s added)
35IBANbanks.lang (29 - IBAN number)
bills.lang (376 - IBAN)
36BICbanks.lang (32 - BIC/SWIFT number)
bills.lang (377 - BIC/SWIFT)
37StandingOrdersbanks.lang (35 - Standing orders)
bills.lang (212 - Standing orders)
withdrawals.lang (3 - Standing orders)
38StandingOrderbanks.lang (36 - Standing order)
bills.lang (213 - Standing order)
withdrawals.lang (4 - Standing orders)
39Accountbanks.lang (61 - Account)
compta.lang (15 - Account)
40SubscriptionPaymentbanks.lang (93 - Subscription payment)
members.lang (138 - Subscription payment)
41Paymentsbills.lang (60 - Payments)
compta.lang (60 - Payments)
42InvoiceRefbills.lang (288 - Invoice ref.)
compta.lang (166 - Invoice ref.)
43NoSupplierOrderboxes.lang (66 - No recorded supplier order)
orders.lang (75 - No supplier order)
44ShowCompanycashdesk.lang (30 - Show company)
companies.lang (289 - Show thirdparty)
45Customercommercial.lang (4 - Customer)
companies.lang (246 - Customer)
46Prospectcommercial.lang (6 - Prospect)
companies.lang (244 - Prospect)
propal.lang (12 - Prospect)
47ContractStatusClosedcontracts.lang (9 - Closed)
products.lang (67 - Closed)
48ExportsAreaexports.lang (2 - Exports area)
other.lang (224 - Exports area)
49NewExportexports.lang (4 - New export)
other.lang (230 - New export)
50ExportableDatasexports.lang (6 - Exportable dataset)
other.lang (228 - Exportable data)
51AvailableFormatsexports.lang (27 - Available formats)
other.lang (225 - Available formats)
52LibraryUsedexports.lang (29 - Library used)
other.lang (226 - Librairy used)
53LibraryVersionexports.lang (30 - Version)
other.lang (227 - Version)
54CreateUserinstall.lang (54 - Create owner)
users.lang (29 - Create user)
55Naturemembers.lang (153 - Nature)
products.lang (151 - Nature)
56OrderDateorders.lang (9 - Order date)
suppliers.lang (9 - Order date)
57Stockproducts.lang (37 - Stock)
stocks.lang (15 - Stock)
58Stocksproducts.lang (38 - Stocks)
stocks.lang (16 - Stocks)
59Movementsproducts.lang (39 - Movements)
stocks.lang (18 - Movements)
60Suppliersproducts.lang (72 - Suppliers)
suppliers.lang (2 - Suppliers)
61ListOfStockMovementsproducts.lang (79 - List of stock movements)
stocks.lang (21 - List of stock movements)
62Unitproducts.lang (153 - Unit)
stocks.lang (30 - Unit)